Bug#494746: cyrus-imapd-2.2: connect(/var/run/cyrus/socket/lmtp) failed: Permission, denied

[Magnus Danielson]

I have found that running this command overcomes the problem without 
messing with bits.

adduser postfix mail

Essentially, for postfix to be able to see the socket:s it needs the 
permissions. Letting the user postfix be part of the mail group is less 
intrusive than letting everyone access the bits, so 750 for permissions 
is correct rather than the workwaround 755.

The cyrus-installer could just do this once and for all, including 
upgrades. That should resolve this bug.

Cheers,
Magnus