[TriLUG] Postfix Woes

Michael Hrivnak mhrivnak at triad.rr.com
Wed Apr 13 02:09:32 EDT 2005


The only settings I had to change to get that functionality are these:

mydomain = somewhere.com
mydestination = $mydomain (and possibly other things)

More comments are intermingled.  Also, there are postfix wizards on this list 
that may have more to say on the matter.

On Wednesday 13 April 2005 01:27 am, Aaron Bockover wrote:
> Okay, having never worked with Postfix or any email system before, other
> than web-based user administration on my shared hosting systems, diving
> head first into the world of email systems is slightly overwhelming,
> considering the time restrictions I am under.
>
> I am right now just working with Postfix. I have the server set up, and
> it is delivering mail into user Maildirs (/home/user/Maildir). I can
> connect to the SMTP server from localhost and send a message without a
> problem. I can connect via telnet from my desktop (which is on a
> completely separate network), actually through port 26 (set up a
> iptables rule on the server to forward 26->25, thanks Earthlink!) and
> send a message.

Make sure that such a remote connection can only send a message to your local 
domain.  And are you saying that inbound port 25 is filtered?

>
> The problem is sending a message through Earthlink's SMTP server, as set
> up in Evolution. My Postfix server is denying the message relayed from
> the Earthlink SMTP server.

I'm guessing that's because earthlink's smtp server is trying to connect to 
port 25 on your machine, which apparently they filter.  Their relay has no 
way of knowing that your machine is running smtp on a non-standard port.  The 
only way around this that I see is to have an smtp server somewhere else on 
the net to which inbound port 25 is not filtered.  That smtp server is setup 
simply as a relay for your domain, but not the destination.  Then you could 
use the transport map to specify that any connections to your destination 
machine occur on a different port.  You'd need an entry 
in /etc/postfix/transport such as:

somewhere.com     smtp:[somewhere.com]:26

Any time that file is changed, you need to run:

postmap /etc/postfix/transport

And, of course, in your MX record you specify that remote machine as the 
primary email server for your domain.



>
> I was thinking that the "mynetworks" and "mynetworks_style" settings in
> main.cf have something to do with this?
>
> Does anyone have a config that I can work with that handles the
> following goals:
>
> 1. Accept incoming SMTP connections from anywhere and messages bound for
> the local server
> 2. Do not relay messages from any other host except the local server
> (and other hosts manually specified) to remote SMTP servers

mynetworks_style = host

>
> If I can get mail delivered from any SMTP server to mine, then I think I
> can really get going with Postfix, and move on to virtual domains and
> users, and then getting Courier-IMAP set up to read the Maildirs.
>
> I'd also appreciate any other Postfix/Courier-IMAP related
> tips/tricks/articles that anyone may have to share! Email is the only
> system I'm not too familiar with! It'd be more fun if I had more
> time :-/
>
> Thanks!
>
> Aaron Bockover



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