近期不少站点管理员发现，网站流量出现明显波动，排查后发现一个常被忽视的环节——禁 ping。所谓禁 ping，就是在服务器安全设置中屏蔽了 ICMP 协议，导致搜索引擎的爬虫服务器无法通过 ping 来探测网站是否存活。很多人认为这能减轻服务器负担、防止攻击，但实际上，禁 ping 对 SEO 会产生一系列连锁反应，最直接的表现就是抓取频次下降、新内容收录变慢。

ICMP的全名是Internet Control and Message Protocal即因特网控制消息/错误报文协议，这个协议主要是用来进行错误信息和控制信息的 ...

Hey all,<P>I've written some code to ping. I have two versions, one that uses icmp.dll and one that uses raw sockets. Both work just fine.<P>The problem with raw sockets is that it must be run under ...

The current IP address scheme of 32-bit words is fast becoming inadequate. It would appear that 2 32 = 4 294 967 296 combinations of addresses should be enough for everybody, but in practice this is ...