I do it like this
at the end of the acl_check_rcpt section after I check the HELO commands are valid
drop message = "Unknown user"
condition = ${lookup{${lc:$local_part@$domain}} dbm{/etc/mail/hm-users.db} {false}{true} }
domains = +relay_to_domains
seems to work very well for me.
On Mon, 24 Sep 2007 11:07:37 +0100 , Robert Bannocks <rbannocks@???> wrote:
>I am looking into building tables of known users at my border routers.
>currently the border (mail) routers run exim and accept all e-mail for
>our domains. This is unsatisfactory because lots of spam gets to the
>border machines and then gets a 550 from the messages stores which
>results in lots of undeliverable bounces. I have been thinking of ways
>to validate addresses at the border machine. One way would be to have a
>router of the form.:
>
># check the local_part of all validate_domains against the database
>address_check:
> driver = redirect
> domains = +validate_domains
> data = ${lookup{$local_part}lsearch{/usr/local/exim/aliases.$domain}}
> repeat_use=false
> forbid_exim_filter
> forbid_pipe
> forbid_file
> no_more.
>
>Another would be to use an ACL to check addresses for valid_domains. A
>3rd might be to use SMTP call outs.
>
>Which of these is the most efficient? Am I correct in presuming that
>using ACL is the most efficient, followed by using routers followed by
>using callouts?
>My reasoning is that using ACLs will mean that compared to using routers
>for invliad addresses all the routers up to the addresses_check router
>will not be needed to run. Am I correct in assuming the connection lag
>for Callouts will be far greater than using a local copy of the valid
>addresses in an alias file. Of course I may make use of a DBM or CDB
>file in the real implementation...
>
>Are their any pitfalls in using ACL? Are their any other methods?
>
>Any opinions and experiences welcome.
>
>TIA and regards
>
>Rob
>
>
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--
Oliver Howe
Senior Systems Administrator
Tel: +44 (0) 79 7420 6484
Fax: +44 (0) 20 7664 7878
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