Testing Dovecot in Postfix or Verify Dovecot in Postfix

One thing that you can do is run this command to verify it is listening on the correct port numbers:

netstat -aunt

This should show that Dovecot is listening on ports 143 and 110 for IMAP and POP3.

Check if Dovecot is Listening
Another test is to connect to Dovecot using telnet on port 143.  Here is an example with the output you want.

telnet localhost 143
Trying 127.0.0.1…
Connected to localhost.
Escape character is ‘^]’.
* OK dovecot ready.

Check if Dovecot Accepting Passwords
telnet localhost 143
Trying 127.0.0.1…
Connected to localhost.
Escape character is ‘^]’.
* OK dovecot ready.
1 login hemanth
1 login hemanth password
1 OK Logged in.

Check if Dovecot is Accepting Remote Logins
telnet 21.14.126.132 143
Trying 21.14.26.132…
Connected to 21-14-26-132.static.example.net (21.14.126.132).
Escape character is ‘^]’.
* OK dovecot ready.
1 login hemanth password
1 OK Logged in.Check if Dovecot is Finding the Mailbox
1 select inbox
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags permitted.
* 0 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1163363765] UIDs valid
* OK [UIDNEXT 1] Predicted next UID
1 OK [READ-WRITE] Select completed.