Exim logging outgoing helo_data

Question

I have an exim email server that is used for multiple websites. It uses a different host string for helo_data for each website that it serves. DNS and rDNS for each applicable host string is properly set-up.

I want to be to log in the exim mainlog which host string was used for each email sent.

Is this possible and if not, what are my options to know which host string was used in HELo on a per email basis?

Thank you

Answer 1

If you can decide upon the helo data in the ACL stage, you can assign it to an $acl_m_... variable ($acl_m_outbound_helo), which can be referenced anywhere in the lifetime of the message. You probably want to do this in the DATA ACL, based entirely upon the sender, not the recipient.

You can then use log_message in that same ACL to log the value; it will go into the mainlog together with the Exim message id, for correlation. Then in the transport, you just reference that same $acl_m_outbound_helo to use for the connection.

Answer 2

Unfortunately there is no built-in method for logging the helo_data variable to the mainlog file.

The method I would probably use would either to be to add a hook somewhere within the message path to log the data I am looking for to another file with some reference to point back to the entries in the mainlog file (say the message ID), or I would set up a separate router & transport on a per-website basis. The transport used to send the mail is logged in the mainlog file as the T=my_transport value.

For the custom logging I have managed to do something similar for inserting of received email details into a database using the condition = value in the router. You could use the ${run{<command> <args>}} string expansion to achieve this:

condition = ${run{/path/to/interpreter /path/to/custom/logging/script $sender_domain $message_exim_id}{1}{0}}

(untested)

That little snippet in the router will execute the script /path/to/custom/logging/script using the interpreter /path/to/interpreter (/bin/sh, /usr/bin/perl, whatever) passing it the domain name of the sender and the Exim message ID.

It's fairly heavyweight, so wouldn't be ideal on a heavy usage server, but it might just work....