Postfix won't start

Just noticed I wasn't receiving system mail for the last few weeks. Coming back after holiday. Anyway, one of the few services not to restart after the computer had been switched off in my absence was postfix.

Couldn't for the life of me work out the problem, it was complaining about not finding the host. Therefore I had a look in /etc/hosts and commented out the line below:

#
# hosts         This file describes a number of hostname-to-address
#               mappings for the TCP/IP subsystem.  It is mostly
#               used at boot time, when no name servers are running.
#               On small systems, this file can be used instead of a
#               "named" name server.
# Syntax:
#
# IP-Address  Full-Qualified-Hostname  Short-Hostname
#

127.0.0.1       localhost


# special IPv6 addresses
#::1             localhost ipv6-localhost ipv6-loopback

fe00::0         ipv6-localnet

ff00::0         ipv6-mcastprefix
ff02::1         ipv6-allnodes
ff02::2         ipv6-allrouters
ff02::3         ipv6-allhosts

The one about IPv6. Dunno what that was about - but it works now.