[Pkg-exim4-users] can't connect to port 25 from other than localhost

[Derek Stevenson]

I've just installed and configured exim, spamassassin, and cyrus on a 
clean debian install and have them working together ok, except for one 
(fairly major!) detail: I can't seem to have exim handle inbound 
messages from anything other than localhost.

 From the same host (10.2.1.111), I can telnet to port 25:

10.2.1.111# telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.localdomain.
Escape character is '^]'.
220 localhost.localdomain ESMTP Exim 4.50 Tue, 23 Aug 2005 00:30:17 -0700

However, if I try to telnet from another computer in my local net, I 
can't connect:

10.2.1.110# telnet 10.2.1.111 25
Trying 192.168.1.111...
telnet: connect to address 192.168.1.111: Connection refused

I spent a while digging through iptables to see if the default debian 
setup comes with certain filter rules that block port 25 connections 
from the outside, but I don't think this is the case (again, this is 
unchanged from the default debian setup):

10.2.1.111# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

So now I'm thinking it's something in the exim config itself that's 
blocking external port 25 connections, but the only things I've done to 
customize the default exim config files is add a couple routers and 
transports for cyrus and spamassassin, nothing else.

Help!  Does anyone have any advice on next steps?

Thanks,
Derek