SymptomsOn a just deployed QMail host the Dovecot service cannot be started:
# service dovecot restart
Stopping Dovecot Imap: [FAILED]
Starting Dovecot Imap: If you have trouble with authentication failures,
enable auth_debug setting. See http://wiki.dovecot.org/WhyDoesItNotWork
This message goes away after the first successful login.
Error: socket() failed: Address family not supported by protocol
Fatal: listen(::, 143) failed: Address family not supported by protocol