DOvecot requires both IPv4 and IPV6 to start

I think we are off topic.

We have a network policy that until such time as we have fully implemented the same security we have on our IPV4 network we simply do not allow IPV6 as it is another attack vector we are not fully upto speed on. So we block all IPV6 at the perimeter and on all switches, firewalls and routers. So if you connect to our network with a device no IP6 is configured and only IPV4 is allowed. We will get there!

But that is not this issue. The issue is that dovecot is assuming that IPV6 is there and crashes out if it's not. Hacking the config to only listen on IP4 solves the problem but not while installing from standard repos to install the currently supported version.

Cheers Spart