用Firefox浏覽網頁的時候，一開始總會看到左下角有一行提示：
“正在解析主機 xxx ...”
看上去是等待DNS服務器對域名的解析，於是閒來無事，決定做一個DNS Cache來提高下速度！
找了一下，有一個：
[xport@Ubuntu ~] $ apt-cache search "dns" | fgrep "cach"
dnsmasq - A small caching DNS proxy and DHCP server
去翻翻資料，設定的步驟如下：
1. 安裝dnsmasq：
# 安裝dnsmasq的軟件包
[xport@ubuntu ~] $ sudo apt-get install "dnsmasq"
2.設定dnsmasq接管本機的DNS解析請求：
# 修改dnsmasq的配置文件
[xport@ubuntu ~] $ sudo gedit /etc/dnsmasq.conf
# 找到下面的內容，並進行修改
# If you want dnsmasq to listen for DHCP and DNS requests only on
# specified interfaces (and the loopback) give the name of the
# interface (eg eth0) here.
# Repeat the line for more than one interface.
# interface=
# Or you can specify which interface _not_ to listen on
# except-interface=
# Or which to listen on by address (remember to include 127.0.0.1 if
# you use this.)
listen-address=127.0.0.1 # 把這一行前面的注釋去掉
3.修改dhclient的配置：
# 修改dnsmasq的配置文件
[xport@ubuntu ~] $ sudo gedit /etc/dhcp3/dhclient.conf
# 找到下面的內容，並進行修改
prepend domain-name-servers 127.0.0.1; # 把這一行前面的注釋去掉
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, host-name,
netbios-name-servers, netbios-scope;
4.修改resolv.conf的配置：
[xport@ubuntu ~] $ sudo gedit /etc/resolv.conf
# 因為dnsmasq會接管本機的DNS解析請求，所以把127.0.0.1的地址放在最前面
nameserver 127.0.0.1
nameserver xxx.xxx.xxx.xxx
nameserver xxx.xxx.xxx.xxx
search localdomain
5. 重新開啟dnsmasq的服務：
[xport@ubuntu ~] $ sudo /etc/init.d/dnsmasq restart
