Description of problem:
A problem likely identical to bug 1263229 has been encountered in squid on RHEL 6. When squid is configured to log fully qualified domain names, reverse DNS lookup is never performed for the first request.

Version-Release number of selected component (if applicable):
squid-3.1.23-9.el6

How reproducible:
always

Steps to Reproduce:

On server machine:
$ cat <<EOF >> /etc/squid/squid.conf
log_fqdn on
logformat fqdn %>A %>Hs "%rm %ru"
access_log /var/log/squid/fqdn.log fqdn
EOF
$ echo OK > /var/www/html/test
$ service httpd start
$ service squid start

On client machine:
$ curl http://<SERVER_NAME>/test -x [<SERVER_IPV6>]:3128 > /dev/null
$ curl http://<SERVER_NAME>/test -x [<SERVER_IPV6>]:3128 > /dev/null
$ curl http://<SERVER_NAME>/test -x [<SERVER_IPV4>]:3128 > /dev/null
$ curl http://<SERVER_NAME>/test -x [<SERVER_IPV4>]:3128 > /dev/null

On server machine:
$ cat /var/log/squid/fqdn.log

Actual results:
<SERVER_IPV4> 200 "GET http://<SERVER_NAME>/test"
<SERVER_NAME> 200 "GET http://<SERVER_NAME>/test"
<SERVER_IPV6> 200 "GET http://<SERVER_NAME>/test"
<SERVER_NAME> 200 "GET http://<SERVER_NAME>/test"

Expected results:
<SERVER_NAME> 200 "GET http://<SERVER_NAME>/test"
<SERVER_NAME> 200 "GET http://<SERVER_NAME>/test"
<SERVER_NAME> 200 "GET http://<SERVER_NAME>/test"
<SERVER_NAME> 200 "GET http://<SERVER_NAME>/test"