On Mon, 2011-04-04 at 09:51 -0500, Russell Jones wrote: > Hello! > I am having a strange issue with CentOS 5.4 that I cannot seem to solve. > Every DNS lookup results in AAAA records being requested first before A > records. As a result, this causes a large amount of unnecessary DNS > traffic on the network. IPv6 has been completely disabled on these servers: Doubtful, if you are seeing AAAA lookups. Does "ip addr" show any IPv6 interfaces? > /etc/modprobe.conf, ipv6 off and net-pf-10 off > /etc/sysconfig/network, NETWORKING_IPV6=no > lsmod | grep ipv6 shows the kernel module no longer loaded. > Yet watching TCP dump shows that AAAA records are requested before A > records every time a login is requested from one of our local machines > to another You *only* sees these for login? Perhaps some authentication module you are using is causing them to happen? > Is there some sort of configuration directive I can use to > force IPv4 lookups first before IPv6? Or even better, stop IPv6 lookups > all together? I don't believe you see IPv6 lookups from the normal resolver libraries unless there is at least one active IPv6 interface.