[Esd-l] HELP on a mail gateway =(

Ian Castle ian.castle at coldcomfortfarm.net
Fri Aug 9 12:19:02 PDT 2002

On Thu, 2002-08-08 at 23:29, Ing Juan Pablo Feria wrote:
> I m trying to create a mail-gw  to protect an i-mail server with the
> document included on pm-sanitizer, but i have a question, how does my
> sendmail box the address of my imail box?

The first thing to do is to get your sendmail box working nicely as a
relay *before* trying to adapt it for email santising.

A simple approach is to 

- Make your relay machine know about your domain by putting an entry in
the sendmail.cw (local-host-names as it is called in recent versions).

- Create a "local user relay" entry to automatically forward any email
to your mailserver. What this really does is to forward any mail
addressed to a mailbox (i.e. the LHS of the "@") that is NOT in
/etc/passwd - so "root at example.com" will arrive at the relay...

- Make sure that you allow relaying from your email server so that
outgoing mail is delivered (/etc/mail/access).

- Set up your relay as the smart host on your mail/smtp server

- It is also good to have  an MX record for your domain pointing at your

Note that if your domain is "example.com" and your relay is
"relay.example.com" and your postoffice server is "pop.example.com" then
mail addressed to "fred at example.com" will arrive at the mail server as
"fred at pop.example.com" so it is important that the destination
recognises these as a local address.

Once you've got this set up you can follow the setup instructions for
the sanitizer as a relay.

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