杭州电信DNS
 202.101.172.35
 202.101.172.47
wget https://thekelleys.org.uk/dnsmasq/dnsmasq-2.78.tar.gz
 tar xvf dnsmasq-2.78.tar.gz
 cd dnsmasq-2.78
 make
 sudo make install
sudo /usr/local/sbin/dnsmasq
检查DNS服务器服务开启(53端口)
 telnet x.x.x.x 53
 Ctrl + ]
 quit
 # CentOS6
 iptables -L -n 
 iptables -I INPUT -m state --state NEW -m tcp -p tcp --dport 53 -j ACCEPT
 iptables -I INPUT -m state --state NEW -m udp -p udp --dport 53 -j ACCEPT
 /etc/init.d/iptables save
 /etc/init.d/iptables restart
# CentOS7
 default_zone=$(firewall-cmd --get-default-zone) # public
 firewall-cmd --permanent --zone=${default_zone} --add-port=53/tcp
 firewall-cmd --permanent --zone=${default_zone} --add-port=53/udp
 firewall-cmd --reload
能ping通,但是telnet ip port 提示
Trying x.x.x.x...
 telnet: connect to address x.x.x.x: No route to host
服务端lsof -i:端口号,有输出
[user@vultr dnsmasq-2.78]$ sudo lsof -i:53
 COMMAND   PID   USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
dnsmasq 23058 nobody    4u  IPv4 131090      0t0  UDP *:domain 
 dnsmasq 23058 nobody    5u  IPv4 131091      0t0  TCP *:domain (LISTEN)
 dnsmasq 23058 nobody    6u  IPv6 131092      0t0  UDP *:domain 
 dnsmasq 23058 nobody    7u  IPv6 131093      0t0  TCP *:domain (LISTEN)
说明防火墙的问题
欢迎使用 Microsoft Telnet Client Escape 字符为 'CTRL+]' Microsoft Telnet> quit
yum provides */dig
sudo yum install bind-utils