*Something* has clearly changed here.
Can you confirm that the SMTP server is running and listening on port 25 and/or 478?
Can you confirm that port 25 and/or 478 are open and reachable from your OTRS server to the SMTP server? Nothing's going to work unless that's true. You can test that with telnet (telnet <host> <port>).
If you get a banner or a prompt for authentication, then you know the ports are open. Pingable tells you nothing these days; you have to test the specific application ports you care about to determine if traffic can flow.
If this doesn't work, then the problem is likely a firewall issue.
Can you confirm that you can manually construct a message from a telnet session originating from the OTRS server to port 25 on the SMTP server? EG:
telnet <smtphost> 25
and type:
HELO otrs.server.at.your.domain
MAIL FROM: mailto:foo@your.domain>
RCPT TO: mailto:you@your.domain>
DATA
Test
.
QUIT
You should see "202 Message accepted" or something similar. If you get any other response, the problem is your SMTP server's configuration.
Can you confirm that your OTRS machine has correct forward and reverse DNS entries that match and are resolvable from another system other than the SMTP server and OTRS server? Most modern SMTP system will not accept mail from a system that does not have correct DNS.
I'd start with those steps, and then check userid and pw if you're using authenticated SMTP.
From: otrs-bounces@otrs.org [mailto:otrs-bounces@otrs.org] On Behalf Of Gadow, Shawn
Sent: Monday, August 20, 2012 2:10 PM
To: User questions and discussions about OTRS.
Subject: Re: [otrs] Can't send e-mail replies after upgrade to 3.1.2
How would an upgrade to otrs affect the SMTP server settings/blocking? I apologize for my ignorance on the subject it just don't make sense to me that something that the SMTP which was working prior to upgrade would be changed post upgrade when it was not touched
From: otrs-bounces@otrs.orgmailto:otrs-bounces@otrs.org [mailto:otrs-bounces@otrs.org]mailto:[mailto:otrs-bounces@otrs.org] On Behalf Of Gerald Young
Sent: Monday, August 20, 2012 12:55 PM
To: User questions and discussions about OTRS.
Subject: Re: [otrs] Can't send e-mail replies after upgrade to 3.1.2
Impossible to send is impossible to send. If you're still getting that, your SMTP server is blocking your ability to send.