Should be '404 Not Found'.
$ curl -v
www.v2ex.com/404* About to connect() to
www.v2ex.com port 80 (#0)
* Trying 106.187.41.232... connected
* Connected to
www.v2ex.com (106.187.41.232) port 80 (#0)
> GET /404 HTTP/1.1
> User-Agent: curl/7.21.4 (universal-apple-darwin11.0) libcurl/7.21.4 OpenSSL/0.9.8r zlib/1.2.5
> Host:
www.v2ex.com> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Wed, 02 May 2012 02:32:06 GMT
< Content-Type: text/html; charset=UTF-8
< Connection: keep-alive
< Content-Length: 69
< Etag: "4d29230fb65c836072b3802c4cb3a9fd7c10e8be"
< Server: TornadoServer/2.2
< Set-Cookie: V2EX_LANG=en; Path=/
<
* Connection #0 to host
www.v2ex.com left intact
* Closing connection #0
<html><title>404: Not Found</title><body>404: Not Found</body></html>
这是一个专为移动设备优化的页面（即为了让你能够在 Google 搜索结果里秒开这个页面），如果你希望参与 V2EX 社区的讨论，你可以继续到 V2EX 上打开本讨论主题的完整版本。
https://www.v2ex.com/t/34337
V2EX 是创意工作者们的社区，是一个分享自己正在做的有趣事物、交流想法，可以遇见新朋友甚至新机会的地方。
V2EX is a community of developers, designers and creative people.