1,234
edits
Changes
→Testing
Which one is it? Find the port used by SMTP, and look for connctions with the state LISTEN (i.e. currently listening).
== Testing the connection to Postfix ==
Connect from your server to your server using telnet:
<source lang="bash">telnet localhost 25</source>
Note that it will tell you once your connect that '''Escape character is '^]''', which means your can hold control and press the square bracket key to end the session (and then exit the telnet app).
If this worked - that means the service is running and listening and responding to connections. Let's see if it works from other machines. Telnet to vm2 from the host (connect to the SMTP port) and see if it works. If yourfirewall is set up properly - it shouldn't, you'll need to allow incomming connections to TCP port 25. Once you open the port in the firewall - try the telnet command. You should get a different error this time. This time the problem is that your service isn't listening on the outside interface, it's currently configured to listen only on the loopback (lo) interface.