Re: [exim] building mail gateway

On 27 Oct 2004, Genady Perchenko wrote:

[generating collateral spam - bounces]

> If emails arrives to the prime server. the recipient is checked at mail
> acception time and rejected right away if no valid recipient found. In
> this case no bounced message is generated. However, if mail happened to
> land to the secondary server, then validation of the recipient did not
> happened yet and mail has been accepted in good faith to pass alone to
> the prim server later. Prime server rejects it due to invalid recipient
> thing but the secondary server just sort of caught in the middle and
> left alone dealing with email it should of not taking in the first place
> if it knew upfront that recipient is not valid. How would I deal with
> this?

With one of two ways:

a) (the VERY easy way) use recipient callouts. With Exim 4, this takes
about 5 seconds. Just add "/callout" to "verify = recipient" in the RCPT
ACL. I don't think you can do this at all with Exim 3, though I could be
completely wrong.

b) push your valid recipient list to the secondary server(s). You can do
this by any means you want - it could be scp'ing text/DBM files, using a
shared database (LDAP, MySQL, whatever...) or whatever you want. You then
use a router to check recipients against the list (even though deliveries
will not actually take place on that server). I'm pretty sure you could do
this with Exim 3.

> I host email for over 300 domains with over 2000 email addresses (pops
> and forwards) spread over 300 alias files. all maintains been done
> through the home build control panel. Before I can upgrade to ver 4, I
> need to run it first on non production server and see what is involved
> in migration of all my existing setups to the new version. I actually
> thinking to use this new gateway as a test field to see what I woudl
> need to change in my alias files to migrate to the ver 4.

How about you just put Exim 4 on the secondary server(s) for now? From
what you said, it sounds like they are just "dumb" secondary MXes in which
case, the config is probably pretty much default. By putting Exim 4 on the
secondar(y|ies), you can immediately stop the collateral spam problem
without having to spend ages looking into a new configuration. Then, when
you have time, you can look into configuring it on your main machine, and
in the meantime you will be able to assess your requirements more
accurately without the confusion of lots of collateral spam unnecessarily
loading your machines.

> Hey, how come when I hit reply to your message, I am sending message to
> you and not to the list?

Because that's how the list is set up. Some mailing lists change the
Reply-To header but this list does not. Don't even go there; there will be
lots of arguments (with no ultimate agreement) about which way is correct.

If your mail client has a "List Reply" function, that should work.
Otherwise, you may be able to set it up manually to recognise that this is
a mailing list with a special address.

> What is wrong?

Nothing.


Tim