A netfilter module, use can use iptables to match DNS domain.
# make KERNEL_SRC=<your kernel source> IPTABLES_SRC=<your iptables source> install
# iptables -m domain -h
domain v0.0.3 options:
--name "www.chinaunix.net" Match the domain named "www.chinaunix.net"
--name "chinaunix.net" Match the domain named "chinaunix.net"
include www.chinunix.net, bbs.chinaunix.net, man.chinaunix.net
kernel: >= 2.6.38
iptables: >= 1.4.11