wget 提示unable to resolve host address的原因

下载 nginx 报错

[root@CTN-QD-247 ~]# wget -c http://nginx.org/download/nginx-1.12.0.tar.gz
--2017-05-09 12:37:18--  http://nginx.org/download/nginx-1.12.0.tar.gz
Resolving nginx.org... failed: Temporary failure in name resolution.
wget: unable to resolve host address “nginx.org”

原因

检查 iptables 发现没放行53端口

[root@CTN-QD-247 ~]# iptables -A INPUT -p tcp --dport 53 -j ACCEPT
[root@CTN-QD-247 ~]# iptables -A INPUT -p udp --sport 53 -j ACCEPT
[root@CTN-QD-247 ~]# iptables -A INPUT -p tcp --sport 53 -j ACCEPT
[root@CTN-QD-247 ~]# iptables -A INPUT -p udp --dport 53 -j ACCEPT