Ken Rossman wrote:
1) I can "telnet localhost 25" on system "A" and that works (gets through to sendmail just fine).
2) If instead I used the command "telnet A 25", I get the following: "telnet: connect to address xxx.xxx.xxx.xxx: Connection refused"
3) I get the same "Connection refused" message when trying to telnet to port 25 on system A from any other system on the LAN (as I guess I would expect).
This is not a firewall issue at all, but a sendmail issue (assuming that you have a default Red Hat install of sendmail). Please see this document:
http://www.simpaticus.com/linux/sendmail-smtp-auth-howto.html
It will show you how to let sendmail accept connections from outside your machine, and will also show you how to activate SMTP AUTH so that your machine is not abused as an open relay (not just a security hole, but also an opportunity for spammers).
I have just rewritten a decent chunk of this document a couple of days ago, so I think you'll find the information very useful. Post again to the list if there is something you don't understand or if something does not work the way you prefer, and feel free to write me directly with any feedback or questions on the HOWTO.
Cheers,
-- Rodolfo J. Paiz rpaiz@xxxxxxxxxxxxxx
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