[H-GEN] Mail hosting

[Tony Nugent]

On Wed Mar 10 2004 at 11:03, "Tony Melia" wrote:

> This is probably a basic sendmail question, but I have a few small clients
> that have their own mail servers (mostly exchange 2k) are struggling with
> spam and mail viri, who do not have the capabilities to use
> antispam/antivirus software.

 [real solution here is to exchange exchange for a linux box running
 sendmail or similar... I haven't any experience with any of them
 myself, but I hear that some of the groupware products for linux
 are starting to become mature enough to make this a very serious
 consideration:-]

> If I redirect their MX records to my domain,
> can I get sendmail accept mail for their domain, filter it as per normal
> spamassasin/inflex scanning, and then deliver the mail back to them at their

  [for email filtering with sendmail, I can highly recommend
  mimedefang... http://www.mimedefang.org/ and Can-It, its
  commercial version... http://www.canit.ca/]

> domain (even though their MX records points to my server), I assume I would
> have to tell my sendmail to not use normal DNS rules when delivering the
> mail back to them?

This can be done, and you need to do exactly like that, and this is
usually achieved by using the mailertable file (usually in
/etc/mail/).[1]

  [1] you'll need to run "make" or manually run makemap to
  re-generate the mailertable.db file.  BTW, you don't need to
  "killall -HUP sendmail" after a configuration change to any of the
  .db files.

For details on how the mailertable file is used, see the README file
that comes with the sendmail "cf" (configuration) package.  Mmm, you
could probably use the domaintable to do the same thing.

Make sure (whatever you use) that it is enabled in the sendmail.cf
file.  (You'll need to HUP sendmail if the .cf file is changed).

You'll also need to update the "local-host-names" and/or
"relay-domains" files so that sendmail will actually accept email
for those domains (besides your own) that you are wanting to act as
MX for.

Ultimately, by casting the right magic in all these files, it is
possible for you to redirect any specific email received for anyone
to just about anywhere you like...

Have fun!

> Regards,
> Tony

Cheers
Tony