Milter-greylist

> > X-Greylist: Message not sent from an IPv4 address, not delayed by
> > milter-greylist-x.y .
> 
> Did you disable the IPv6 support in Milter Greylist?
> 
> True64 has a dual network stack and "sendmail" might be using an IPv6
> socket even for IPv4 connections.

The attached patch removes some code asymmetry in the IPv4 - IPv6 relation.
There is no functionality changes. The most important part that it may produce more
accurate error messages such as instead of
"Message not sent from an IPv4 address"
it gives
"Message not sent from an IPv4 neither IPv6 address"
if IPv6 support is compiled in.

Bests,
Attila