> This problem only affects emails from our internal mail domains. These
> users send mail via authenticated smtp sessions via our mta's running
> exim. I was hoping there would be a more elegant approach using exim
> routers to make the emails from authenticated sender do a DNS check
> and if it is internal then check the list of local domains before
> sending mail internally. If the DNS points externally then the mail
> should go to the external destination thus solving the problem.
>
> Could someone knowledgeable about exim routers let me know if there is
> possible?
Almost anything is possible in Exim routers, because they are very
powerful and Exim has powerful conditional execution features. However
the flipside of this power is that writing routers can be very close to
writing a program in a programming language. The consequence of this
is that it's extremely unlikely that anyone here can (or will) write
a set of routers for you that will do what you need. Instead we can
only suggest that you read the Exim documentation on routers and on
string expansions carefully and then try to build a set of routers with
appropriate 'condition =' and so on settings.
People here can probably suggest answers for focused router-related
questions like 'what is the best way to check MX entries for something'
or 'how do I use LDAP data in routing decisions', though.
- cks
