Can't Telnet to Port 25 except from localhost

I’m having trouble getting postfix to accept any email. If I am ssh’d into the machine I can telnet localhost 25 and get a ESMTP but I can’t telnet to the box from outside of it.

The firewall reports port 25 is open
Accept If protocol is TCP and destination port is 25 and state of connection is NEW.

Many ISPs block port 25.

You’ll either need to talk to them about it (probably fruitless), or configure Postfix to also listen on one or more other ports. If you have an SSL certificate, you could enable smtps and/or submission. If not, just copy the smtp line and set it up on port 2525.

My ISP does not block any ports at all, as I am on a dedicated business connection for the express purpose of hosting. We have other machines all running mail services on the same pipe.

I have no experience with Postfix and am extremely interested in your comment "If not, just copy the smtp line and set it up on port 2525."

For the purpose of troubleshooting Postfix, I’ve been looking for a line that looks just like that and haven’t found one. Where might I find such a line, in Cause if so, mine’s missing…

When I first set up the box, I installed sendmail. I’ve since turned sendmail off, but have been unsuccessful with postfix in general on this machine. Works fine on the other box I’m trying Virtualmin on… but that box is exactly what you guys suggested: CentOS installed virgin with… not much hope I can get that kind of install on this box, so, I’ve been really struggling with postfix.

The line Joe was referring to is in the file.

Postfix should work without a hitch – so I’m sure we can either get it working, or at least quickly nail down what the issue is :slight_smile:

What is the output of these two commands:

postconf -n

iptables -L -n

Also, when you attempt to telnet in, do you see any messages in mail or messages log in /var/log?

switching sendmail off and turn postfix on doesn’t work too well I believe.
There is a command to switch MTA. Im sure eric and joe will know it, sorry I forget cmds all the time myself :confused: (old brain)

True that.

I turned sendmail off using webmin, then used the desktop’s GUI to turn it off as a service, then turned on postfix as a service, then used webmin to turn postfix on, then rebooted the machine…

Is there something else I might have missed?

alternatives --config mta

Is the command ronald was searching brain for. If I didn’t have to use it every month or so, I would forget it, too. :wink: