wget一个网站很慢的原因

今天wget一个网站时，发现很慢：

 # wget www.baidu.com
 ---- ::--  http://www.baidu.com/
 Resolving www.baidu.com... 14.215.177.38, 14.215.177.37  ##此处停顿约5秒
 Connecting to www.baidu.com|14.215.177.38|:... connected.
 HTTP request sent, awaiting response...  OK
 Length:  (.3K) [text/html]
 Saving to: “index.html.”

 %[============================================>] ,       --.-K/s   in 0s      

 -- :: ( MB/s) - “index.html.” saved [/]

默认会优先解析 IPv6，在那个 domain 没有 IPv6 的情况下，会等待 IPv6 解析失败 timeout 之后才按以前的正常流程去找 IPv4

 [root@web02 scripts]# wget - www.baidu.com
 ---- ::--  http://www.baidu.com/
 Resolving www.baidu.com... 14.215.177.38, 14.215.177.37
 Connecting to www.baidu.com|14.215.177.38|:... connected.
 HTTP request sent, awaiting response...  OK
 Length:  (.3K) [text/html]
 Saving to: “index.html.”

 %[============================================>] ,       --.-K/s   in 0s      

 -- :: (96.3 MB/s) - “index.html.” saved [/]

瞬间完成