Squid send malformed PTR query for IPv6 address. This affects logging FQDN.
patch is in the upstream bug
If squid is configured to log fqdn, there should be hostname instead of host ip. With squid-3.1.10-29, there is correctly hostname displayed in log, but with previous version of squid reverse lookup failed an ip address was displayed instead.
logformat fdqn %>A %>Hs "%rm %ru"
access_log /var/log/squid/fdqn.log fdqn
2620:52:0:1040:dad3:85ff:fe7e:6068 200 "GET http://[2620:52:0:10bb:21e:67ff:fe94:7c67]/
some.host.redhat.com 200 "GET http://[2620:52:0:10bb:21e:67ff:fe94:7c67]/"
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.