* Wakko Warner <wakko@???> [20030520 03:26]: wrote:
> > Okay, hit me with the duh stick if this is already something that's been
> > asked... Is there a comprehensive 3.36 -> 4.x upgrade howto? I know I can't
> > just drop in my old /etc/exim.conf and expect it to work.
>
> Try reading the spec.txt and using convert4r4. It may or may not product an
> equivilant config for 4.x to use. But You can use that as a guide. I did,
> but threw it away in favor of configureing the entire thing by hand.
Since this question has been asked many times, I'll take leave to give an
answer once and for all.
When Philip released Exim-3.59, these are the notes that he gave about
upgrade from Exim-3.x to the new Exim-4.x:
Perhaps Nigel should prominently put the document that was named Exim4.Upgrade
somewhere on the website?? I believe it's wrong for me to send that document
in-line to a mailing list because of bandwidth considerations.
##########################################################################
Upgrading Exim from Release 3.33 to 4.xx
----------------------------------------
Exim 4.00 represents the largest upheaval in Exim's history. There are a lot of
changes to the way some parts of Exim work, and a lot of incompatible changes
to the runtime configuration file.
This document is in two parts. The first part contains instructions and
suggestions for how you might go about performing the upgrade. The second part
is a brief list of all the changes that have taken place. For full details of
all the new features, please consult the reference manual.
HOW TO UPGRADE YOUR EXIM
------------------------
When you compile Exim 4, a Perl script called convert4r4 is built in the build
directory. It is not installed by the install script, because it is likely that
you will run it only once.
This script is provided to assist in updating Exim configuration files. It
reads an Exim 3 configuration file on the standard input, writes a modified
file on the standard output. It also writes comments about what it has done to
the standard error file. It assumes that the input is a valid Exim 3
configuration file. A typical call to the conversion script might be
./convert4r4 </etc/exim/configure >/etc/exim/configure.new
The output file should be checked and tested before trying to use it. Each
option change is preceded by an identifying comment. In fact, the conversion
script tends to make quite a mess of your configuration, and you should expect
to go through it afterwards and tidy it up by hand.
Unless you are running a very straightforward configuration, the automatic
conversion is likely to generate a non-optimal configuration. You should not
only check it thoroughly, but also run as many tests as you can, to ensure that
it is working as you expect. In particular, you should test address routing,
using -bt and -bv, and the policy controls, using -bh. If possible, you should
also do some live tests (i.e. send and receive some messages) before putting
Exim 4 into service.
If you have a very complicated configuration, it is possible that convert4r4
will break it in some situations, which is why thorough testing is strongly
recommended. You Have Been Warned.
One way of upgrading Exim from a pre-4.00 release is as follows:
1. Suppose your configuration file is called /usr/exim/configure, and you want
to continue with this name after upgrading. The first thing to do is to make
another copy of this file called, say, /usr/exim/configure.pre-4.00.
2. Rebuild your existing Exim to use the copy of the configuration file instead
of the standard file. Install this version of Exim under a special name such
as exim-3.33, and point a symbolic link called "exim" at it. Then HUP your
daemon. You can check on the name of the configuration file by running
exim -bP configure_file
Ensure that everything is running smoothly. You now have something you can
fall back to.
3. Build the new release, configured to use the standard configuration file.
4. Use the convert4r4 utility to upgrade your configuration file for the new
release. After running it, check the file by hand, and tidy it up.
5. Test, test, test!
6. You can run complete tests, including actual deliveries, from an uninstalled
binary, but you have to tell it where it is, so that any re-executions can
be done. You can do this by temporarily inserting a setting such as
exim_path = /source/exim/exim-4.00/build-SunOS5-5.8-sparc/exim
into the runtime configuration. If you want to, you can also insert settings
for spool_directory and log_file_path to divert those away from their normal
places. Remember to remove these temporary settings when you eventually
install the binary!
7. The new installation script installs the new release as exim-4.00, and
set a symbolic link called "exim" to point to it.
8. You can now easily change between the new and old releases simply by moving
the symbolic link and HUPping your daemon. The format of message files on
Exim's spool has _not_ changed, so there should be no problem in changing
between releases while there are messages on the queue.
WHAT HAS NOT CHANGED IN EXIM 4.00
---------------------------------
The basic overall philosophy, design, and process structure has not changed.
The format of spool files is the same. The transports have had only minor
modifications. The command line options remain the same, with a couple of
additions.
The general configuration approach has not changed, but the actual details of
the configuration file are different.
The Exim monitor has not changed, and there have been only very minor changes
to other Exim utilities.
WHAT HAS CHANGED IN EXIM 4.00
-----------------------------
The rest of this document lists the very many changes that have taken place.
I'm going to give only brief details here, because this part of the document is
intended as a way of alerting you to areas of difference. The reference manual
describes how the new features work in detail.
Named domain, host, address, and local part lists
-------------------------------------------------
A new feature makes it possible to give names to lists of domains, hosts,
addresses, and local parts. The syntax used is
domainlist <name> = <a domain list>
hostlist <name> = <a host list>
addresslist <name> = <an address list>
localpartlist <name> = <a list of local parts>
For example:
domainlist local_domains = *.my.domain
addresslist bad_senders = cdb;/etc/badsenders
These lists are referenced in options by giving the name preceded by a + sign.
For example, in a router you might have
domains = +local_domains
At first sight, these lists might seem to be the same as macros, but they are
not. Macros are just textual substitutions. If you write
ALIST = host1 : host2
auth_advertise_hosts = !ALIST
it probably won't do what you want, because that is exactly the same as
auth_advertise_hosts = !host1 : host2
Notice that the second host name is not negated. However, if you use a host
list, and write
hostlist alist = host1 : host2
auth_advertise_hosts = ! +alist
the negation applies to the whole list, and so that is equivalent to
auth_advertise_hosts = !host1 : !host2
These named lists also have a performance advantage. When Exim is routing an
address or checking an incoming message, it caches the result of tests on the
lists. So, if you have a setting such as
domains = +local_domains
on several of your routers, the actual test is done only for the first one.
However, this caching works only if there are no expansions within the list
itself. In other words, caching happens only if the list is known to be the
same each time it is referenced.
By default, there may be up to 16 named lists of each type. This limit can be
extended by changing a compile-time variable.
The use of domain and host lists is recommended for concepts such as local
domains, relay domains, and relay hosts. The default configuration is set up
like this.
Processing of domain, host, local part, and address lists
---------------------------------------------------------
The handling of these lists is now more uniform. Every list is expanded as a
single string before it is used. (In Exim 3, some options were expanded and
some weren't, and query-style lookup items were then re-expanded.)
If an expansion is forced to fail, Exim behaves as if the item has not been
found in the list.
The confusing $key variable has been abolished. When processing a domain list,
$domain contains the relevant domain and can be used in generating database
queries. Other appropriate variables are set when processing other kinds of
list; $sender_host and $sender_host_address for checking incoming hosts and
$host and $host_address for checking outgoing hosts.
Note that this means that any \ and $ characters in regular expressions must be
escaped if they appear in one of these lists. The new expansion feature to turn
off expansion (\N ... \N) which is described below can be helpful here.
The details of the processing of address lists has been revised.
If an item in a host list is the empty string, it matches only when no host is
defined. For example, if used when checking an incoming message, it matches
only when the message is arriving by SMTP on the standard input from a local
process (using -bs).
Merge of Directors and Routers
------------------------------
There are no longer any directors in Exim 4. There are just routers. All
addresses are passed to a single list of routers which typically makes use of
the "domains" option to choose which way to handle specific groups of domains.
A consequence of this is that the code no longer contains any concept of "local
domains". However, a typical configuration will probably define a named domain
list (see above) called local_domains, and use it to control routing something
like this:
route_remote:
driver = dnslookup
domains = ! +local_domains
transport = remote_smtp
no_more
system_aliases:
....
The first router does DNS routing for all domains that are not in the named
list of local domains, and no_more ensures that it is the last router for those
domains. All other domains fall through to the system_aliases and subsequent
routers. For a complete configuration example, look at the default
configuration file in src/configure.default.
Router Actions
--------------
The concepts of how the routers work are as follows:
A number or pre-tests are run (details below). If any of them fails, control
is passed to the next router. We say "the router is skipped". Otherwise the
router is run, and can yield one of several different results:
. skip: The pre-conditions for running the router are not met. The address
is passed to the next router.
. accept: The router accepts the address, and either queues it for a transport,
or generates one or more "child" addresses. Processing the original address
ceases, unless "unseen" is set on the router, in which case the address is
passed to the next router. Processing of any child addresses starts with the
first router by default, or at the router defined by redirect_router if it is
set. This may be any router in the list.
. decline: The router declines to accept the address because it does not
recognize it at all. The address is passed to the next router, unless no_more
is set, in which case the address fails.
. pass: The router recognizes the address, but cannot handle it itself. It
requests that the address be passed to another router. This overrides no_more.
By default the address is passed to the next router, but this can be changed by
setting pass_router. However, in this case (unlike redirect_router) the named
router must be below the current router (to avoid loops).
. fail: The router determines that the address should fail, and queues it for
the generation of a bounce message. There is no further processing of the
original address, unless "unseen" is set.
. defer: The router cannot handle the address at the present time. (For
example, a database may be offline.) No further processing of the address
happens in this delivery attempt. It is tried again next time.
. error: There is some error in the router (for example, a syntax error in
its configuration). The action is as for defer.
Router pre-tests
----------------
In Exim 3 there are some strange interactions between the generic options that
test things before running a director or router and the no_more test that
happens afterwards.
In Exim 4 it is all more straightforward. If any fail, the router is skipped
and control passes to the next router. The no_more option has an effect only if
the router is actually run - that is, if all the pre-tests succeed. The order
in which these tests are run is:
verify status, expn status, domains, local_parts, check_local_user
If all those match, the debug_print string is output when debugging. Exim then
goes on to test
senders, require_files, condition
Note that require_files comes near the end of the list, so you cannot use it to
check for the existence of a file in which to lookup up a domain, local part,
or sender. However, as these options are all expanded, you can use the "exists"
expansion condition to make such tests. The require_files option is intended
for checking files that the router may be going to use internally, or which are
needed by a specific transport (e.g. .procmailrc).
In Exim 4, local part prefixes and suffixes are recognized and removed before
any of the pre-tests are done (in Exim 3 they were removed afterwards). Note
that this means that the local_parts option now tests the local part without
its prefix or suffix.
If you want to do pre-tests on local parts that include any affixes, you can do
so by using a "condition" option that uses the variables $local_part,
$local_part_prefix, and $local_part_suffix as necessary.
A New Set of Routers
--------------------
The two sets of routers and directors of Exim 3 have been replaced by a single
set of routers for Exim 4. These are as follows:
. accept Always accepts an address. It has no private options.
. dnslookup Routes by DNS lookup (descended from lookuphost).
. ipliteral Routes IP literal addresses (unchanged).
. iplookup Special-purpose lookup router (unchanged).
. manualroute Routes domains from explicit data (descended from domainlist).
. queryprogram Routes addresses by running a program (detail changed).
. redirect Redirects addresses; handles all the functions previously
supported by aliasfile, forwardfile, and smartuser without
a transport.
Generic Router Options
----------------------
. The global locally_caseless option is replaced by a generic router option
called caseful_local_part. By default, routers handle local parts caselessly.
. check_local_user is now a generic option that is needed to check for a local
account. Typically used on redirect (for user's forward files) and on accept
(for local deliveries).
. The setting self=local has been removed (since there's no concept of local
domains in the code). The same kind of effect can be achieved by using
self=reroute or self=pass.
. expn is now a generic router option.
. local_part_prefix and local_part_suffix are now generic router options,
replacing prefix and suffix on directors.
. Exim 3 has two logging styles for delivery, depending on whether the domain
is a local domain or not. For local domains, the address is given just as the
local part - this makes these deliveries easier to spot in the log. In Exim 4
there's no concept of local domains, so this functionality cannot be
automatic. Instead, there's a generic router option called log_as_local which
requests "local-style" logging. This option defaults on for the "accept"
router, and off for all the others.
. There's an option called retry_use_local_part which is the default for any
router that has check_local_user set, and it applies to routing delays. (The
same option for the appendfile, pipe, and lmtp transports applies to
transport delays.)
. transport_home_directory and transport_current_directory are new generic
options on all routers. They set up default values for home_directory and
current_directory on the transport to which they route an address. Any
settings in the transport override.
. If transport_home_directory is not set, but check_local_user is set, the
user's home directory is used as a default value.
. The special fudge that exists in Exim 3 for handling home_directory settings
in forwardfile directors is not needed in Exim 4. It has therefore been
removed.
. The new_director option in Exim 3 allows the direction of redirected
addresses to start at a given director, instead of the first one. In Exim 4,
this option is now called redirect_router. The option is used when a redirect
router succeeds, and when a queryprogram router returns a "redirect"
response.
. There is a new option called pass_router, which specifies the router to go to
when a router "passes" on an address. The named router must follow the
current router (to avoid routing loops). Note: if a router declines, control
always passes to the next router, unless no_more is set.
. There is a new router option called address_data. This is set to a string
which is expanded just before the router is run, that is, after all the
pre-tests have succeeded. If the expansion is forced to fail, the router
declines. Other expansion failures cause delivery of the address to be
deferred.
When the expansion succeeds, the value is retained with the address, and can
be accessed using the variable $address_data. Even if the router declines or
passes, the value remains with the address, though it can be changed by
another address_data setting on a subsequent router. If a router generates
child addresses, the value of $address_data propagates to them.
The idea of address_data is that you can use it to look up a lot of data for
the address once, then then pick out parts of the data later. For example,
you could use an LDAP lookup to return a string of the form
uid=1234 gid=5678 mailbox=/mail/xyz forward=/home/xyz/.forward
In the transport you could then pick out the mailbox by a setting such as
file = ${extract{mailbox}{$address_data}}
This makes the configuration file less messy, and also reduces the number of
lookups. (Exim does cache the most recent lookup, but there may be several
addresses with different lookups.)
. When a transport is run for several addresses simultaneously, the values of
$address_data, $local_part_data, and $domain_data are taken from the first
address that the transport handles. However, the order in which multiple
addresses are processed is not defined. You therefore need to be careful if
you want to use these variables with multiple addresses. The smtp transport
is the only one which by default handles multiple addresses.
. When an address is routed by a router with the "unseen" option set, a "clone"
address is created, and it starts being routed at the next router. (This is
what people expect. In Exim 3 it starts at the top - in simple cases that has
the same effect because of the anti-looping rule, but if aliases are involved
it sometimes doesn't do what you want.)
. The way that require_files works has been changed. Each item in the list is
now separately expanded as the test proceeds. The use of leading ! and +
characters is unchanged. However, user and group checking is done differently.
Previously, seteuid() was used, but seteuid() is no longer used in Exim (see
"Security" below). Instead, Exim now scans along the components of the file
path and checks the access for the given uid and gid. It expects "x" access
on directories and "r" on the final file.
Other Consequences of the Director/Router Merge
-----------------------------------------------
. The -odqr option is abolished, as there is no inbuilt concept of remote
domains.
. The -odqs option is equivalent to queue_smtp_domains = *.
. queue_remote_domains is renamed queue_domains, and applies to any domain.
. The -ql option now suppresses remote delivery; routing always happens.
. The "remote" facility of queue_only_file has been removed.
. The match_directory option for forwardfile and localuser has been entirely
abolished. Its function can be achieved using the "condition" option in
conjunction with check_local_user.
. When an address is being verified, if it is redirected to a single new
address, verification continues with that address. If it is redirected to
more than one address, verification ceases with a success result. (In Exim 3,
this applied only to aliasing, not to forwarding.)
The dnslookup router
--------------------
This router replaces the lookuphost router of Exim 3. It is much the same,
except that the "gethostbyname" option has been removed. It now does only DNS
routing - hence the change of name. Routing using gethostbyname() can be done
by the manualroute router.
The manualroute router
----------------------
This is the new name for the domainlist router, supposedly to make its function
clearer and to avoid confusion with the "domainlist" that is used to set up
named domain lists. Several things have been removed and reorganized.
. The old search mechanism (route_file, route_query, route_queries,
search_type) have been removed. Instead there is a new option called
route_data, which is an expanded string. It should expand to a single routing
entry. If the expansion ends up empty (or is forced to fail), the router
declines. The route_list option still exists, for convenient listing of a few
inline routes.
. There is no longer any MX processing function in this router. The keywords
bydns_mx and bydns_a have been removed, leaving just
bydns => find IP addresses from address records in the DNS
byname => find IP addresses by calling gethostbyname()
The default lookup type is "byname", and this can be omitted from a route
data line. If an IP address is given, both "byname" and "bydns" are ignored
(so typically you omit this field).
. The qualify_single and search_parents options have also been removed.
. A transport is always required to be set, unless verify_only is set.
. The host_find_failed option can be set to "decline", to cause the router to
decline if it can't find an IP address for a listed host.
. If manualroute routes to a local transport, there is no need to specify
byname or bydns in the routing data. Any supplied host list is passed as a
string in $host, but $host_address is unset.
The queryprogram router
-----------------------
This router has been re-designed:
. You must now specify a user and group for the program to be run using
command_user and (if necessary) command_group. It no longer defaults to
"nobody". These options are expanded.
. The command is now split up and each argument expanded separately, as happens
for the pipe transport. The command name is also expanded.
. The return value "forcefail" has been renamed "fail", and it causes delivery
to fail. (The original usage of "fail" meaning "decline" has finally been
removed.)
. The $route_option variable, which queryprogram used to be able to set has
been abolished. A facility to set the new $address_data variable replaces it.
. The string returned from queryprogram must now be one of:
DECLINE
FAIL text
DEFER text
PASS
FREEZE text
REDIRECT text
ACCEPT TRANSPORT=transport HOSTS=host list LOOKUP=byname|bydns DATA=text
The text returned for "redirect" is a list of new addresses. The text for FAIL
is returned in the SMTP dialogue when the router is run as part of address
verification. It is also logged. The text for DEFER and FREEZE is just logged.
The data items in the "accept" return can be given in any order, and all are
optional. If no transport is included in the "accept" return, the router's
default transport is used. The host list and lookup type are needed only if the
transport is an smtp transport that does not itself have a host list. The
default lookup type is "bydns". If the "data" field is set, its value is placed
in the $address_data variable.
The redirect router
-------------------
This router replaces forwardfile, appendfile, and the use of smartuser without
a transport. It has two mutually exclusive options for specifying data that it
uses. If "file" is set, the data is taken from a file. Otherwise "data" must be
set, and the data is the expanded value of that option.
The data may be an alias list, possibly including special entries such as
:fail:, or it may be a list of filtering instructions.
If "file" is set, but the file does not exist or is empty, or its contents have
no effect (entirely comments, or a filter that does nothing), the router
declines. This also happens if the expansion of "file" is forced to fail. Any
other expansion failure causes the router to defer.
Ownership of the file is checked if check_local_user is set or if owners is
set, unless check_owner is explicitly set false.
Likewise, the group is checked if owngroups is set, or if check_local_user is
set and a modemask not containing 020 is set, unless check_group is explicitly
set false.
If "data" is set, a forced expansion causes the router to decline. This also
happens if "data" is an empty string or a string that causes nothing to be
generated and no action to be taken.
Because "data" is now used for traditional /etc/aliases lookups, an empty alias
no longer gives an error. It behaves in the same way as :unknown: (which is
still recognized, but ignored).
. If no_repeat_use is set, the router is skipped if _any_ ancestor of the
current address was routed by this router. This pre-test happens before any
of the others. (Contrast the the default loop avoidance logic, which skips a
router if an ancestor with the same local part was routed by the router.)
. If include_directory is set, :include: files are constrained to this
directory.
. When an address is redirected to a file or a pipe, $address_file or
$address_pipe (as appropriate) is set when expanding the value of
file_transport or directory_transport.
. There are new options forbid_filter_readfile and forbid_filter_run to lock
out the use of the new ${readfile and ${run expansion items in filters.
. If one_time is set, forbid_pipe, forbid_file, and forbid_filter_reply are
forced to be true, and headers_add and headers_remove are forbidden.
Generic transport options
-------------------------
. All remote deliveries are now done in subprocesses running with specified
UIDs and GIDs. (Formerly, only parallel delivery was done in a subprocess.)
As a result, user and group are now generic options that can be used on all
transports. The default for both local and remote transports is to run as
the Exim user and group. For remote transports, this should not normally be
changed, but it if is, the user or group should be able to access the hints
databases, though failure to open a hints database is always ignored.
If it turns out that a transport user is in the never_users list, Exim now
defers delivery and writes to the panic log. (Previously it just ran the
delivery as "nobody".)
. initgroups is now also a generic transport option.
. home_directory and current_directory are generic options on all transports,
though some transports (e.g. smtp) make no use of them. If they are unset,
values supplied by the router are used.
. The message_size_limit option is now expanded, which makes it possible to
have different limits for different hosts, for example.
Multiple (batch) deliveries in the appendfile, lmtp, and pipe transports
------------------------------------------------------------------------
The options controlling batch deliveries, including BSMTP, were a mess, and
have been reworked.
. The batch option has been removed from all three transports, and the bsmtp
and bsmtp_helo options have been removed from appendfile and pipe.
. The batch_max option defaults to 1 in all three transports.
. A new option called use_bsmtp has been added to appendfile and pipe. When
set, the message is delivered in BSMTP format. If you want to have a HELO
line at the start of the message, you can configure this by making use of the
message_prefix option. You must include the terminating newline.
. A new option called batch_id has been added to all three transports.
Batching is now achieved by setting batch_max to a value greater than 1. This
is recommended for lmtp. When multiple addresses are routed to the same
transport that has a batch_max value greater than one, the addresses are
delivered in a batch, subject to certain conditions:
. If any of the transport's options contain a reference to "$local_part", no
batching is possible.
. If any of the transport's options contain a reference to "$domain", only
addresses with the same domain are batched.
. If batch_id is set, it is expanded for each address, and only those addresses
with the same expanded value are batched.
. Batched addresses must also have the same errors address (where to send
delivery errors), the same header additions and removals, the same user and
group for the transport, and if a host list is present, the first host must
be the same.
The appendfile transport
------------------------
. The prefix and suffix options have been renamed message_prefix and
message_suffix to avoid confusion with address affixes. The default values,
which are suitable for mbox deliveries, now apply only if "file" is set and
use_bsmtp is not set. Otherwise, the default values for these options are
unset. They can, of course, always be overridden.
. If "directory" is set (which means that "file" is not set), the check_string
and escape_string options now default unset.
. The require_lockfile options has been abolished. If use_lockfile is set, a
lock file is always required.
. The quota_filecount option is now expanded.
. The create_file option now also applies when delivering into an individual
file in a given directory, as well as when appending to a single file. In the
case of maildir delivery, the restriction applies to the top directory of the
maildir folder.
The pipe transport
------------------
. The prefix and suffix options have been renamed message_prefix and
message_suffix to avoid confusion with address affixes. The default values
that are suitable for vacation deliveries now apply only if use_bsmtp is not
set. Otherwise the default values for these options are unset. They can, of
course, always be overridden.
The smtp transport
------------------
. The badly-named batch_max option is now called connection_max_messages.
. If hosts_randomize is set, it now affects host lists that come from a router
as well as the contents of the "hosts" option, but only if the hosts were not
obtained from MX records. Typically, such lists come from the manualroute
router. This change means that the router can provide the same host list for
multiple addresses - causing them all to be sent to the transport at once.
Randomizing is then done each time the transport is called. (If you set
hosts_randomize on the router, the randomizing happens for each address.)
. The way that smtp operates when there are multiple addresses to be sent to
the same host is now different. Previously, the transport was called many
times, with a maximum of max_rcpt addresses per call. Each call made a new
connection to the host. When remote_max_parallel = 1, all the addresses are
now passed to the transport at once. It makes a single TCP/IP call, but may
send multiple copies of the message, each with no more than max_rcpt
recipients.
When remote_max_parallel is greater than 1, a heuristic is used. The number
of addresses passed to a single call of the transport is limited to
(the total number of recipients) / (the value of remote_max_parallel)
so, for example, if there are 100 recipients and remote_max_parallel is 2, no
more than 50 are passed in one call, even if max_rcpt is 100. (The idea is
that the other 50 will be passed to another call running in parallel.)
Just in case this leads to trouble (messages with thousands of recipients
have been seen) there is a control on this mechanism called
max_copies_per_connection. It limits the number of copies that the transport
will send down one connection, and the default value is 50. If you set this
option to 1, the effect is to revert to the way Exim 3 does it.
. The "interface" option is now expanded. If the result is a forced failure or
an empty string, it is ignored. Otherwise, the result must be a list of IP
addresses. The first one of the correct type (IPv4 or IPv6) for the outgoing
connection is used. If there isn't one of the correct type, the option is
ignored.
. At the start of running the transport, the value of $host is taken from the
first host in a multi-host list. However, just before the transport connects
to a host, the value is changed to refer to that particular host. (This
applies to $host_address as well.) This means that options such as helo_data
and the tls_options can be made host-specific.
. The tls_verify_ciphers option has been renamed tls_require_ciphers, in order
to leave the word "verify" as something that refers to the verification of
certificates.
The System Filter
-----------------
. The system filter options that were called message_filter_xxx have all been
renamed as system_filter_xxx.
. The value of system_filter is expanded.
. message_filter_directory_transport and message_filter_file_transport are now
both expanded before use. If the filter set up any file or pipe deliveries,
$address_file and $address_pipe are set as appropriate while doing the
expansions.
. message_filter_directory2_transport has been removed. The effect of using
different directory-style transports can be achieved by specifying a suitable
expansion string to system_filter_directory_transport.
. When a system filter added recipients to a message, Exim 3 added an
X-Envelope-To: header, listing the real recipients (up to 100). This has been
abolished because you can do this kind of thing using "headers add" nowadays.
. The "fail" command has been extended to allow for two different messages, one
for Exim's log and the other to be returned to the sender. The syntax is
fail "<<log message>>user message"
That is, if the first two characters of the message are "<<" the following
text, up to ">>", is written to the log, and the remainder is returned to the
user. If there is no log message, the user message is logged. The motivation
for this feature was to reduce the amount of text logged, while being able to
send quite long (maybe even multi-line) messages back to the sender.
Changes to Lookups
------------------
. Oracle support is available. It works like the mysql and pgsql support,
except that there is no "database name" involved, and the "host name" field
is used for what is called "service name" in Oracle. This often looks like a
host name. Also, semicolons are not used at the end of an SQL query for
Oracle.
. There's a new single-key lookup type called dsearch. It searches a directory
for a file whose name matches the key. The result of a successful search is
the key. One possible use of this could be for recognizing virtual domains.
If each domain is represented by a file whose name is the domain name, you
needn't make a separate list of the domains. You could test for them in an
ACL (see below), for example, by a line like this
accept domains = dsearch;/etc/virtual/domains
. The format of LDAP output has been changed for cases where multiple
attributes are requested. The data for each attribute is now always quoted.
Within the quotes, the quote character, backslash, and newline are escaped
with backslashes and commas are used to separate multiple values for the
attribute. Thus, the string in quotes takes the same form as the output when
a single attribute is requested. If multiple entries are found, their data is
still separated by a newline.
. There is now support for the "whoson" mechanism for doing "POP-before-SMTP"
authentication. This is provided by new query-style lookup type called
"whoson", with queries that consist of IP addresses. For example, in an ACL
you can write
require condition = ${lookup whoson {$sender_host_address}{yes}{no}}
Special items in domain and host lists
--------------------------------------
. In a domain list, the special item @ matches the primary host name, and the
special item @[] matches any local interface address enclosed in square
brackets (as in domain literal email addresses). The special item @mx_any
matches any domain that has an MX record pointing to the local host. The
special items @mx_primary and @mx_secondary are similar, except that the
first matches only when the primary MX is to the local host, and the second
only when the primary MX is not the local host, but a secondary MX is.
. In a host list, the special item @ matches the primary host name, and the
special item @[] matches any local interface address (not in brackets).
Access Control Lists (ACLs)
---------------------------
All the policy control options for incoming messages have been replaced by
Access Control Lists (ACLs). These give more flexibility to the sysadmin, and
allow the order of testing to be specified. For example, using an ACL, it is
possible to specify "accept if authenticated, even if from an RBL host, but
otherwise deny if from an RBL host", which is not possible in Exim 3.
ACLs are defined in a new part of the configuration file, and given names.
Which ones to run are controlled by a new set of options that are placed in the
main part of the configuration.
acl_smtp_auth specifies the ACL to run when STARTTLS is received
acl_smtp_data specifies the ACL to run after a message has been received
acl_smtp_etrn specifies the ACL to run when ETRN is received
acl_smtp_expn specifies the ACL to run when EXPN is received
acl_smtp_rcpt specifies the ACL to run when RCPT is received
acl_smtp_vrfy specifies the ACL to run when VRFY is received
The default actions vary. If acl_smtp_auth is not defined, STARTTLS is always
accepted (and an attempt is made to set up encryption on the session). If
acl_smtp_data is not defined, no checks are done after a message has been
received, and it is always accepted at that point.
However, if any of the others are not defined, the relevant SMTP command is
rejected. In particular, this means that acl_smtp_rcpt must be defined in order
to receive any messages over an SMTP connection. The default configuration file
contains a suitable default for this.
ACLs can be provided in line, or in files, or looked up from databases. One ACL
can call another in a subroutine-like manner. String expansion is used, and
which ACL to run can be varied according to sender host or any other criterion
that a string expansion can test.
This is not the place to give a full specification of ACLs, but here is a
typical example for checking RCPT commands, taken from the default
configuration. The tests are performed in order.
acl_check_rcpt:
# Accept if source is local SMTP (i.e. not over TCP/IP - undefined host)
accept hosts = :
# Deny if the local part contains @ or % or /
deny local_parts = ^.*[@%/]
# Accept mail to postmaster in any local domain, regardless of the source,
# and without verifying the sender.
accept domains = +local_domains
local_parts = postmaster
# Deny unless the sender address can be verified.
require verify = sender
# Accept if the address is in a local domain, but only if the recipient can
# be verified. Otherwise deny. The "endpass" line is the border between
# passing on to the next ACL statement (if tests above it fail) or denying
# access (if tests below it fail).
accept domains = +local_domains
endpass
message = unknown user
verify = recipient
# We get here only for non-local domains. Accept if the message arrived over
# an authenticated connection, from any host. Rhese messages are usually from
# MUAs, so recipient verification is omitted.
accept authenticated = *
# Reaching the end of the ACL causes a "deny", but we might as well give
# an explicit message.
deny message = relay not permitted
The following options have been abolished as a consequence of the introduction
of ACLs:
auth_hosts, auth_over_tls_hosts, headers_checks_fail, headers_check_syntax,
headers_sender_verify, headers_sender_verify_errmsg, host_accept_relay,
host_auth_accept_relay, host_reject_recipients, prohibition_message,
rbl_domains, rbl_hosts, rbl_log_headers, rbl_log_rcpt_count,
rbl_reject_recipients, rbl_warn_header, receiver_try_verify, receiver_verify,
receiver_verify_addresses, receiver_verify_hosts, receiver_verify_senders,
recipients_reject_except, recipients_reject_except_senders, relay_domains,
relay_domains_include_local_mx, relay_match_host_or_sender,
sender_address_relay, sender_address_relay_hosts, sender_reject,
sender_reject_recipients, sender_try_verify, sender_verify,
sender_verify_batch, sender_verify_hosts, sender_verify_fixup,
sender_verify_hosts_callback, sender_verify_callback_domains,
sender_verify_callback_timeout, sender_verify_max_retry_rate,
sender_verify_reject, smtp_etrn_hosts, smtp_expn_hosts. smtp_verify, tls_hosts.
The variable $prohibition_reasion has been abolished.
The host_reject option has been retained, but with its name changed to
host_reject_connection, to emphasize that it causes a rejection at connection
time. I've left it available just in case it is needed - but its use is not
recommended in normal circumstances.
Other Incoming SMTP Session Controls
------------------------------------
. The option smtp_accept_max_per_connection (default 1000) limits the number of
messages accepted over a single SMTP connection. This is a safety catch in
case some sender goes mad (incidents of this kind have been seen). After the
limit is reached, a 421 response is tiven to MAIL commands.
. Some sites find it helpful to be able to limit the rate at which certain
hosts can send them messages, and the rate at which an individual message can
specify recipients. There are now options for controlling these two different
rates.
Rate limiting applies only to those hosts that match smtp_ratelimit_hosts,
whose value is a host list. When a host matches, one or both of the options
smtp_ratelimit_mail and smtp_ratelimit_rcpt may be set. They apply to the
rate of acceptance of MAIL and RCPT commands in a single SMTP session,
respectively.
The value of each option is a set of four comma-separated values:
1. A threshold, before which there is no rate limiting.
2. An initial time delay. Unlike other times in Exim, fractions are allowed
here.
3. A factor by which to increase the delay each time.
4. A maximum value for the delay.
For example, these settings have been used successfully at the site which
first suggested this feature, for controlling mail from their customers:
smtp_ratelimit_mail = 2, 0.5s, 1.05, 4m
smtp_ratelimit_rcpt = 4, 0.25s, 1.015, 4m
. The default value for smtp_connect_backlog has been increased to 20.
. The SMTP protocol specification requires the client to wait for a response
from the server at certain points in the dialogue. (Without PIPELINING these
are after every command; with PIPELINING they are fewer, but still exist.)
Some spamming sites send out a complete set of SMTP commands without waiting
for any response. Exim 4 protects against this by rejecting messages if the
client has sent further input when it should not have. The error response
"554 SMTP synchronization error" is sent, and the connection is dropped.
This check is controlled by smtp_enforce_sync, which default true.
. helo_strict_syntax has been abolished. The default is now to enforce strict
domain syntax for HELO/EHLO arguments. You can use helo_accept_junk_hosts if
you want to avoid this.
. There's a new option called helo_lookup_domains. If the domain given in a
HELO or EHLO command matches this list, a reverse lookup is done in order to
establish the host's true name. The default setting is
helo_lookup_domains = @ : @[]
That is, a lookup is forced if the client host gives the server's name or
[one of its IP addresses] in HELO or EHLO. (In Exim 3 this happened
automatically and was not configurable.)
. The value of the global message_size_limit option is now expanded. For
locally submitted messages this happens at the start of message reception.
For messages from remote hosts, the expansion is done just after the host
connects, so that the value can depend on the host.
Handling of Resent- Fields
--------------------------
RFC 2822 makes it clear that Resent- fields are purely informational. Exim used
to make use of Resent-Reply-To: which does not actually exist, and it also used
to use the last set of resent- fields for all the address fields it recognized.
In Exim 4, resent- headers are dealt with as follows:
. A Resent-From: header that just contains the login id as the address is
automatically rewritten in the same way as From: is (using qualify domain,
and user name from the passwd data).
. If there's a rewrite rule for a header, it is also applied to resent- headers
of the same type. For example, a rule that rewrites From: headers also
rewrites Resent-From: headers.
. For local messages, if Sender: is being removed on input, Resent-Sender: is
also removed.
. If there are any resent- headers but no Resent-Date: or Resent-From: they are
added.
. The logic for adding Sender: is now duplicated for Resent-Sender.
. If there's no Resent-Message-Id: one is created, and it is the
Resent-Message-Id: which is included in the log line.
Authentication
--------------
. The auth_hosts option has been abolished; this functionality is now
controlled by ACLs.
. The auth_always_advertise option has been abolished because it depended on
auth_hosts and and host_auth_accept_relay, both of which are no more. In its
place there is a new option called auth_advertise_hosts, whose default value
is *, meaning "advertise AUTH to all".
. The value of server_setid is now used when logging failed authentication
attempts.
. The -oMaa option allows trusted users to set the value of
$sender_host_authenticated (the authenticator name). This is normally used in
conjunction with -oMa.
Encryption
----------
. Because tls_hosts is no more, tls_advertise_hosts is now the only means of
controlling the advertisement of STARTTLS (previously, tls_hosts overrode).
. The global option tls_verify_ciphers has been abolished. There are now
facilities for checking which cipher is in use in ACLs.
. There's a new option called tls_try_verify_hosts. Like tls_verify_hosts, this
causes the server to request a certificate from a client, and it verifies the
certificate that it receives. However, unlike tls_verify_hosts, Exim
continues with the SMTP connection (encrypted) if a client certificate is not
received, or if the certificate does not verify. This state can be detected
in an ACL, which makes it possible to implement policies such as "accept for
relay only if a verified certificate has been received but accept for local
delivery if encrypted, even without a verified certificate".
A match in tls_verify_hosts overrides tls_try_verify_hosts.
The Daemon
----------
. local_interfaces can now specify a port number with each address, thus
allowing a single Exim daemon to listen on multiple ports. The format of each
address is either [aaaa]:ppp or aaaa.ppp where aaaa is an IP address and ppp
is a port number. For example:
local_interfaces = 192.168.3.4.25 : 192.168.3.4.26
If an address is listed without a port, the setting of smtp_port, or the
value of the -oX option, is the default.
. The -oX option can now override local_interfaces. That is, it can supply IP
addresses as well as just a port. It is interpreted in this way if its value
contains any of the characters . : or []. For example:
exim -bd -oX 10.9.8.7:10.11.12.13.2525
The format of the string is identical to the format recognized by the
local_interfaces option.
. The way the daemon wrote PID files was overly complicated and messy. It no
longer tries to be clever. A PID file is written if, and only if, -bd is used
and -oX is _not_ used. In other words, only if the daemon is started with its
standard options. There is only one PID file. If pid_file_path is unset, it
is exim-daemon.pid in Exim's spool directory. Otherwise the value of
pid_file_path is used. For backwards compatibility, "%s" in this value is
replaced by an empty string.
Logging
-------
The log_level option and all the various independent logging control options
have been abolished. In their place there is a single option called
log_selector. It takes a string argument composed of names preceded by + or -
characters. These turn on or off the logging of different things. For example:
log_selector = +arguments -retry_defer
The optional logging items (defaults marked *) are:
address_rewrite address rewriting
all_parents all parents in => lines
arguments exim arguments
*connection_reject connection rejections
*delay_delivery immediate delivery delayed (message queued)
delivery_size add S=nnn to deliveyr lines
*dnslist_defer defers of DNS list (aka RBL) lookups
incoming_interface incoming interface on <= lines
incoming_port incoming port on <= lines
*lost_incoming_connection as it says (includes timeouts)
*queue_run start and end queue runs
received_sender sender on <= lines
received_recipients recipients on <= lines
*retry_defer "retry time not reached"
sender_on_delivery add sender to => lines
*size_reject rejection because too big
*skip_delivery "message is frozen"
smtp_confirmation SMTP confirmation on <= lines
smtp_connection SMTP connections
smtp_protocol_error SMTP protocol errors
smtp_syntax_error SMTP syntax errors
subject contents of Subject: on <= lines
*tls_cipher TLS cipher on <= lines
tls_peerdn TLS peer DN on <= lines
all all of the above
"retry time not reached" is always omitted from individual message logs after
the first delivery attempt.
The log line "error message sent to" has been abolished, because the R= item on
the incoming message line gives the relationship between the original message
and the bounce.
The logging options that have been abolished are: log_all_parents,
log_arguments, log_incoming_port, log_interface, log_ip_options,
log_level, log_queue_run_level, log_received_sender, log_received_rceipients,
log_rewrites, log_sender_on_delivery, log_smtp_confirmation,
log_smtp_connections, log_smtp_syntax_errors, log_subject, tls_log_cipher,
tls_log_peerdn.
Debugging
---------
The debug_level option has been removed. The -dm option has been removed. The
-df option has also be removed, along with its related build-time option
STDERR_FILE. (To debug inetd usage, an auxiliary script should be used.)
The -d option has been reworked. It no longer takes a debug level number
argument, but instead takes a list of debugging names, each preceded by + or -
to turn on or off individual sets of debugging messages.
. The -v option now shows just the SMTP dialog and any log lines.
. -d with no argument gives a lot of standard debugging data. This is in effect
the equivalent of the old -d9, the thing you ask people to set for an initial
debugging test.
. -d+x adds debugging option x to the default set
-d-x removes debugging option x from the default set
-d-all+x leaves only debugging option x
The available debugging names are:
acl ACL interpretation
auth authenticators
deliver general delivery logic
dns DNS lookups (see also resolver)
dnsbl DNS black list (aka RBL) code
exec arguments for execv() calls
filter filter handling
hints_lookup hints data lookups
host_lookup all types of name->IP address handling
ident ident lookup
interface lists of local interfaces
lists matching things in lists
load system load checks
lookup general lookup code and all lookups
memory memory handling (replaces the old -dm)
process_info setting info for the process log
queue_run queue runs
receive general message reception logic
resolver turn on the DNS resolver's debugging output; goes to stdout
retry retry handling
rewrite rewriting
route address routing
tls TLS logic
transport transports
uid changes of uid/gid and looking up uid/gid
verify address verification logic
all all of the above, and also -v
The default (-d with no argument) includes all of the above, plus -v, with the
exception of filter, interface, load, memory, and resolver. Some debugging
output always happens unconditionally whenever any debugging is selected. This
includes some initial output and every log line.
-d without any value was previously allowed for non-admin users because it used
to by synonymous with -v. In Exim 4, non-admin users may use -v, but not -d.
If the debug_print option is set in any driver, it produces output whenever any
debugging is selected, or if -v is used.
Local Scan Function
-------------------
For customized message scanning, you can now supply a C function that is linked
into the Exim binary. The function is called local_scan(), and it is called
when Exim has received a message, but has not yet sent a final
acknowledgement to the sender. This applies to all messages, whether local or
remote, SMTP or not.
From within your function you can inspect the message, change the recipients,
add or remove headers, and tell Exim whether to accept or reject the message.
The manual contains the specification of the API for this function.
String Expansion
----------------
. The lookup feature that allowed for subkeys using the syntax
${lookup {key:subkey} type {data...
has been abolished (a) because the effect can be achieved using ${extract,
and (b) because in non-lsearch lookups, a colon can be a valid character in a
key.
. When a string key is used in a ${extract expansion item, it is now handled
case-insensitively.
. A new expansion variable called $tod_epoch gives the time as a single decimal
number representing the number of seconds from the start of the Unix epoch.
. ${extract{number} now recognizes a negative number as a request to count
fields from the right.
. There's a new expansion feature for reading files:
${readfile{/some/file}{eolstring}}
The contents of the file replace the item. If {eolstring} is present (it's
optional) any newlines in the file are replace by that string.
. There's a new expansion feature for running commands:
${run{comand args}{yes}{no}}
Like all the other conditional items, the {yes} and {no} strings are
optional. Omitting both is equivalent to {$value}. The standard output of the
command is put into $value if the command succeeds (returns a zero code). The
value of the code itself is put into $runrc, and this remains set afterwards,
so in a filter file you can do things like
if "${run{x y z}{}}$runrc" is 1 then ...
elsif $runrc is 2 then ...
As in other command executions from Exim, a shell is not used by default.
If you want a shell, you must explicitly code it.
. The redirect router has options for forbidding ${readfile and ${run in
filters.
. A feature is provided to suppress expansion of part of a string. Any
characters between two occurrences of \N are copied to the output string
verbatim. This is particularly useful for protecting regular expressions from
unwanted expansion effects. For example:
queue_smtp_domains = ! \N^ten-\d+\.testing\.com$\N
Without \N the \ and $ characters in the regex would have to be escaped.
. Radius authentication is supported in a similar way to PAM. You must set
RADIUS_CONFIG_FILE in Local/Makefile to specify the location of the Radius
client configuration file. Then you can use expansions such as
server_condition = ${if radius{arguments}{yes}{no}}
Security
--------
Exim 3 could be run in a variety of ways as far as security was concerned. This
has all been simplified in Exim 4. The security-conscious might like to know
that it no longer makes any use of the seteuid() function.
. A UID and GID are required to be specified when Exim is compiled. They can be
now specified by name as well as by number, so the relevant options are now
called EXIM_USER and EXIM_GROUP. If you really feel you have to run Exim as
root, you can specify root here, but is is not recommended.
. The "security" option has been abolished. Exim always releases its root
privilege when it can. In a conventional configuration, that means when it is
receiving a message, when it is delivering a message, when it is running a
queryprogram router, and when it is obeying users' filter files (and system
filters if it has been given a user for that purpose).
. One important change is that Exim 4 runs as root while routing addresses for
delivery. Exim 3 used seteuid() to give up privilege temporarily while
routing. Apart from the unliked use of seteuid(), this sometimes gave rise to
permissions problems on configuration files.
. However, Exim still runs as the Exim user while receiving messages, and
therefore while using the routing logic for verifying at SMTP time.
. There is a new option called deliver_drop_privilege. If this is set, Exim
gives up its privilege right at the start of a delivery process, and runs the
entire delivery as the Exim user. This is the same action that used to be
requested by setting security=unprivileged.
Hints Databases
---------------
. A single "misc" hints database is now used for ETRN and host serialization.
There have been appropriate consequential changes to the utilities for
managing the hints.
. The exim_tidydb -f option has been abolished. A full tidy is now always done
(it hasn't proved to be very expensive).
The Runtime Configuration File
------------------------------
. The format of the configuration file has changed. Instead of using "end" to
terminate sections, it now uses "begin <name>" to start sections. This means
that the sections, apart from the first, may appear in any order.
. You can now include other files inside Exim runtime configuration files, by
using this syntax:
.include <file name>
. Quotes round the file name are option. Includes may be nested to any depth,
but remember that Exim reads its configuration file often. The processing of
.include happens early, at a physical line level, so, like comment lines, it
can be used in the middle of an options setting, for example:
hosts_lookup = a.b.c \
.include /some/file
Include processing happens _before_ macro processing. Its effect is simply to
process the lines of the file as if they occurred inline where the .include
appears.
. A macro at the start of a configuration line can now turn the line into an
empty line or a comment line. This applies to _logical_ input lines, that is,
after any concatenations have been done.
Format of spool files
---------------------
. -local_scan is used in spool files to record the value of $local_scan_data,
the string returned from the locally-provided local_scan() function.
Renamed Options
---------------
Some options have been renamed, to make their function clearer, or for
consistency.
. receiver_unqualified_hosts has been renamed as recipient_unqualified_hosts.
I'm going to use "recipient" everywhere in future.
. helo_verify has become helo_verify_hosts.
. remote_sort has become remote_sort_domains.
. In the appendfile and pipe transports, "prefix" and "suffix" have become
"message_prefix" and "message_suffix". In the generic router options,
"prefix" and "suffix" have become "address_prefix" and "address_suffix".
Miscellanous
------------
. ETRN serialization now uses a double fork, so that an Exim process (detached
from the original input process) can wait for the command to finish. This
means that it works whatever command ETRN causes to run. (Previously it
worked only if ETRN ran "exim -Rxxx".)
. For incoming messages, the server's port number is preserved, and is
available in $interface_port. The privileged option -oMi can be used to
set this value.
. The -Mmd option (to mark addresses delivered) now operates in a
case-sensitive manner.
. Checks for duplicate deliveries are now case-sensitive in the local part.
. The number of situations where Exim panics has been reduced. For example,
expansion failures for the "domains" or "local_parts" options in a router now
cause deferral instead of a panic.
. EXPN no longer attempts to distinguish local and remote addresses (but you
can cause it to be rejected for certain arguments in the ACL).
. accept_timeout has been renamed as receive_timeout, to match
smtp_receive_timeout.
. The ability to check an ident value as part of an item in a host list has
been removed.
. The reject log shows a message's headers only if the rejection happens after
the SMTP DATA command (because they aren't available for earlier checks). The
sender, and up to five recipients are listed in Envelope-from: and
Envelope-to: header lines. After the headers, a line of separator characters
is output. Separators are no longer used for other reject log entries.
. Because header checks are now done as part of ACLs, they now apply only to
SMTP input.
. The port number on SMTP connections is now logged in the format [aaaa]:ppp
where aaaa is an IP address and ppp is a port, instead of in the format
[aaaa.ppp] because the former format causes some software to complain about
bad IP addresses.
. The -oMa and -oMi options can now use the [aaaa]:ppp notation to set a port
number, but they still also recognize the aaaa.ppp notation.
. The build-time option HAVE_AUTH is abolished. Exim automatically includes
authentication code if any authenticators are configured.
. The nobody_user and nobody_group options have been abolished.
. The $message_precedence variable has been abolished. The value is now
available as $h_precedence:.
. There's a new utility script called exim_checkaccess which packages up a call
to Exim with the -bh option, for access control checking. The syntax is
exim_checkaccess <IP address> <email address> [exim options]
It runs "exim -bh <IP address>", does the SMTP dialogue, tests the result and
outputs either "accepted" or "Rejected" and the SMTP response to the RCPT TO
command. The sender is <> by default, but can be changed by the use of the
-f option.
. The default state of Exim is not to forbid domain literals. For this reason,
the option that changes this has been renamed as allow_domain_literals.
. The dns_check_names boolean option has been abolished. Checking is now turned
off by unsetting dns_check_names_pattern.
. The errors_address and freeze_tell_mailmaster options have been abolished. In
their place there is a new option called freeze_tell, which can be set to a
list of addresses. A message is sent to these addresses whenever a message is
frozen - with the exception of failed bounce messages (this is not changed).
. The message_size_limit_count_recipients option has been abolished on the
grounds that it was a failed experiment.
. The very-special-purpose X rewrite flag has been abolished. The facility it
provided can now be done using the features of ACLs.
. The timestamps_utc option has been abolished. The facility is now provided by
setting timezone = utc.
. The value of remote_max_parallel now defaults to 2.
. ignore_errmsg_errors has been abolished. The effect can be achieved by
setting ignore_errmsg_errors_after = 0s. The default value for
ignore_errmsg_errors_after is now 10w (10 weeks - i.e. likely to be longer
than other timeouts).
. The default for message_size_limit is now 50M as a guard against DoS attacks.
. The -qi option does only initial (first time) deliveries. This can be helpful
if you are injecting message onto the queue using -odq and want a queue
runner just to process new messages. You can also use -qqi if you want.
. Rewriting and retry patterns are now anything that can be single address list
items. They are processed by the same code, and are therefore expanded before
the matching takes place. Regular expressions must be suitably quoted. These
patterns may now be enclosed in double quotes so that white space may be
included. Normal quote processing applies.
. Some scripts were built in the util directory, which was a mistake, because
they might be different for different platforms. Everything that is built is
now built in the build directory. The util directory just contains a couple
of scripts that are not modified at build time.
. The installation script now installs the Exim binary as exim-v.vv-bb (where
v.vv is the version number and bb is the build number), and points a symbolic
link called "exim" to this binary. It does this in an atomic way so that
there is no time when "exim" is non-existent. The script is clever enough to
cope with an existing non-symbolic-link binary, converting it to the new
scheme automatically (and atomically).
. When installing utilities, Exim now uses cp instead of mv to add .O to the
old ones, in order to preserve the permissions.
. If the installation script is installing the default configuration, and
/etc/aliases does not exist, the script installs a default version. This does
not actually contain any aliases, but it does contain comments about ones
that should be created. A warning is output to the user.
. A delay warning message is not sent if all the addresses in a message get a
"retry time not reached" error. Exim waits until a delivery is actually
attempted, so as to be able to give a more informative message.
. The existence of the three options deliver_load_max, queue_only_load, and
deliver_queue_load_max was confusing, because their function overlapped. The
first of them has been abolished. We are left with
queue_only_load no immediate delivery if load is high when
message arrives
deliver_queue_load_max no queued delivery if load is too high
. The ability to edit message bodies (-Meb and the Eximon menu item) has been
removed, on the grounds that it is bad practice to do this.
. Eximstats is now Steve Campbell's patched version, which displays sizes in K
and M and G, and can optionally generate HTML.
. If bounce_sender_authentication is set to an email address, this address is
used in an AUTH option of the MAIL command when sending bounce messages, if
authentication is being used. For example, if you set
bounce_sender_authentication = mailer-daemon@???
a bounce message will be sent over an authenticated connection using
MAIL FROM:<> AUTH=mailer-daemon@???
. untrusted_set_sender has changed from a boolean to an address pattern. It
permits untrusted users to set sender addresses that match the pattern. Like
all address patterns, it is expanded. The identity of the user is in
$sender_ident, so you can, for example, restrict users to setting senders
that start with their login ids by setting
untrusted_set_sender = ^$sender_ident-
The effect of the previous boolean can be achieved by setting the value to *.
This option applies to all forms of local input.
. The always_bcc option has been abolished. If an incoming message has no To:
or Cc: headers, Exim now always adds an empty Bcc: line. This makes the
message valid for RFC 822 (sic). In time, this can be removed, because RFC
2822 does not require there to be a recipient header.
. ACTION_OUTPUT=no is now the default in the Exim monitor.
. dns_ipv4_lookup has changed from a boolean into a domain list, and it now
applies only to those domains. Setting this option does not stop Exim from
making IPv6 calls: if an MX lookup returns AAAA records, Exim will use them.
What it does is to stop Exim looking for AAAA records explicitly.
. The -G option is ignored (another Sendmail thing).
. If no_bounce_return_message is set, the original message is not included in
bounce messages. If you want to include additional information in the bounce
message itself, you can use the existing errmsg_file and errmsg_text
facilities.
. -bdf runs the daemon in the foreground (i.e. not detached from the terminal),
even when no debugging is requested.
. Options for changing Exim's behaviour on receiving IPv4 options have been
abolished. Exim now always refuses calls that set these options, and logs the
incident.
Removal of Obsolete Things
--------------------------
. The obsolete values "fail_soft" and "fail_hard" for the "self" option have
been removed.
. The obsolete "log" command has been removed from the filter language.
. "service" was an obsolete synonym for "port" when specifying IP port numbers.
It has been removed.
. The obsolete option collapse_source_routes has been removed. It has done
nothing since release 3.10.
. The obsolete from_hack option in appendfile and pipe transports has been
removed.
. The obsolete ipv4_address_lookup has been abolished (dns_ipv4_lookup has been
a synonym for some time, but it's changed - see above).
. The obsolete generic transport options add_headers and remove_headers have
been abolished. The new names, headers_add and headers_remove, have been
available for some time.
Philip Hazel
October 2001
#############################################################################
-Wash
--
Odhiambo Washington <wash@???> "The box said 'Requires
Wananchi Online Ltd. www.wananchi.com Windows 95, NT, or better,'
Tel: +254 2 313985-9 +254 2 313922 so I installed FreeBSD."
GSM: +254 72 743223 +254 733 744121 This sig is McQ! :-)
If God had meant for us to be naked, we would have been born that way.
