This was discussed in [HACKERS] TCP/IP with 7.4 beta2 broken?
I created a patch to hba.c which uses IPV4 entries as IPV6 entries if
running on a IPV6 system (which is detected from a port coming in as
AF_INET6).
192.168.0.0/24 -> ::ffff:102.168.0/120
192.168.0.0 255.255.255.0 -> ::ffff:102.168.0 ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.0
This helps people that think they're using IPV4 while actually their
system silently is using IPV6 (such as SuSE 8.1, 8.2).
Regards,
Andreas