尽管网络浏览器在同一台计算机上工作，但 Ping 请求超时

Question

我现在在万维网上，在 StackOverflow 上发帖证明了这一点。但是，如果我尝试从命令行ping stackoverflow.com，ping 超时。我需要做什么才能使 ping 正常工作？

> ping stackoverflow.com

Pinging stackoverflow.com [198.252.206.140] with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 198.252.206.140:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

编辑，试试tracert

> tracert stackoverflow.com

Tracing route to stackoverflow.com [198.252.206.140] over a maximum of 30 hops:

  1     *        *        *     Request timed out.
  2     *        *        *     Request timed out.
  3     *        *        *     Request timed out.
  4     *        *        *     Request timed out.
  5     *        *        *     Request timed out.
  6     *        *        *     Request timed out.
  7     *        *        *     Request timed out.
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13     *        *        *     Request timed out.
 14     *        *        *     Request timed out.
 15     *        *        *     Request timed out.
 ...
 Trace complete.

它是Request timed out. 一直到 30 跳。

编辑，试试ping google.com

同样的结果。 :-)

Answer 1

某些主机的防火墙会阻止 ICMP (http://ca.wikipedia.org/wiki/Internet_Control_Message_Protocol) 数据包，例如 ping。您可以使用 traceroute（命令行工具或在线网站，如 http://ping.eu/traceroute/）或 tcptraceroute (http://linux.die.net/man/1/tcptraceroute)。

某些路由器还具有阻止 ICMP 的防火墙。你可以通过ping google.com 检测到这一点。如果它失败了，那么问题是你的本地路由器而不是远程主机。

希望对你有帮助