Hi,

I am writing an application that needs its outgoing mail processed from a sendmail server. More specifically the application needs its outgoing mail checked for a particular keyword in the Subject line. If the keyword matches, the email will be forwarded to a particular group of users.

The incoming message processing was very simple to implement through ~/.procmailrc, but I am struggling with the outgoing part. From what I've gathered I have to add some additional configurations in /etc/mail/sendmail.mc.

I am not familiar with m4 but the configurations start with:
LOCAL_RULESETS
LOCAL_RULE_0

If someone could provide me with the proper configurations or another means of achieving the same end I'd be really grateful.

cheers!

If the keyword matches, the email will be forwarded to a particular group of users.
Why not have mail sent to a distribution alias instead of trying to compensate for what looks like a deficiency in the application forcing a kludge on Sendmail? As far as I know by default outbound email doesn't flow through procmail. If you want to take that route you might want to look for clues at methods / subjects about scanning outbound email (using a SMTP proxy on another port forwarding to the "real" MTA) or those about people needing to tack those ghastly "legal" footers onto outbound email (which nearly always point to using a custom milter).

your suggestion regarding the SMTP proxy worked. I used proxysmtp-1.2.1 to implement outgoing and incoming mail filtering. The trick is to switch around the ports. The proxy is set to listen on port 25 whereas the actual MTA is listening on another port. This way the proxy will be able to filter both incoming and outgoing mail. Once the proxy is finished processing the message it is simply forwarded to the actual MTA.

The problem was that I couldn't simply generate a copy of the message with the 'mail' utility as this would cause an infinite loop to occur. Instead the filtering script had to insert the message into the target user's spool file directly.

echo "From username@domain `date`" >> /var/spool/mail/targetuser
echo "Return-Path: <username@domain>" >> /var/spool/mail/targetuser
cat tmpmessage_file >> /var/spool/mail/targetuser

well thats the short of it anyway. Perhaps not the most elegant solution but it works

The problem could have been handled better within the application itself. However, I am building around legacy modules (no source code available) which only allows one email to be specified in it's configuration files, hence the need for outgoing mail filtering.

Regards