[Mailman-Users] Sendmail and apache on Different Servers

[John McIntyre]

Hi,
I am running several servers, including a mail server (sendmail) which is
primary MX for my domain.  These servers are all behind a router/firewall.

mail.mydomain.com 192.168.1.13
www.mydomain.com 192.168.1.14

I would like to get a mailman instance working, so I install a new VM:

mailman.mydomain.com 192.168.1.15

So I get sendmail up and running on the new server, and can send e-mails,
and they arrive with the correct sender envelope.

External DNS for mydomain.com points to the external IP of my router.

The problem is that there is already a www and mx server, and my router
forwards all traffic on ports 80, 443, 25 and 143 to those two servers.

So how do I get the new mailman server to talk to the outside world?

I'm guessing that apache can proxy for the mailman server, but what about
e-mail?

Any and all help appreciated.