[Exim] Exim 4.20 - Not denying hosts without reverse DNS....

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Szerző: Kevin W. Reed
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Címzett: exim-users
Tárgy: [Exim] Exim 4.20 - Not denying hosts without reverse DNS....
Exim 4.20 - Solaris 9

I was forced to quickly bring up Exim 4.20 due to a change in some clients
ISP that starting blocking Port 25 outbound. Currently I have it setup
and most of the testing is complete with little problems. We are using
this only listening on a different port right with an Exim 3.26 running on
port 25 until we finish testing.

One difference that I have been unable to figure out is that with the old
configuration, we blocked any site that arrived without a valid reverse
dns lookup. We didn't care what the result was, just that there was one.
We also overrode that with a list of users that would get email anyway.

The configuration looked like:

host_lookup = !/usr/local/exim4/host_lookup-exempt : \
    !/usr/local/exim4/net_lookup-exempt : \
    0.0.0.0/0


In both of the files we are checking against, there is list of IP's that
are exempt from this lookup as well.

I noticed that this looks exactly the same as it did in Exim3 which makes
me wonder if it is not setup properly. We used the convert4r4 which
worked pretty good but did mess up in some places.

Note that when we test with an IP that does not have a lookup returned the
LOG indicates it, but even after completing the process and providing a
user that is not exempt, it still lets the message continue.

I'm guessing this is real simple, but I'm missing it.

BTW... I thought the conversion to 4 would be really hard but for the most
part it has been actually pretty easy. The new layout is I think easier
to understand too.

# exim -bh 69.41.70.186

**** SMTP testing session as if from host 69.41.70.186
**** but without any ident (RFC 1413) callback.
**** This is not for real!

>>> host in host_lookup? yes (matched "0.0.0.0/0")
>>> looking up host name for 69.41.70.186
>>> IP address lookup failed: h_errno=1

LOG: no host name found for IP address 69.41.70.186
>>> host in host_reject_connection? no (option unset)
>>> host in sender_unqualified_hosts? no (option unset)
>>> host in recipient_unqualified_hosts? no (option unset)
>>> host in helo_verify_hosts? no (option unset)
>>> host in helo_try_verify_hosts? no (option unset)
>>> host in helo_accept_junk_hosts? no (option unset)

220 DRACO.DOMAIN ESMTP Exim 4.20 Wed, 18 Jun 2003 18:09:38 -0700

[completing with helo, mail to, rcpt to of a user that is not overridden
sill permits the message to continue]. the LOG is the only indication
that the IP had no hostname.


Unrelated and not really needed badly yet....

Is there an example of how I could refer to a list of hosts to see if they
needed to be sent mail on a non-standard smtp port. Like a file that
would contain:

hostname1: 2025
hostname2: 82

If matched, the port command would then be used to send mail to that host
on the port specified.

I figure someone has already done something like this perhaps.


--
Kevin