我试图在Apacheconfiguration文件（httpd.conf）中获取HostnameLookups的含义。 我也对这个指令的目标感兴趣。
谢谢亚历山德罗
http://httpd.apache.org/docs/2.2/mod/core.html#hostnamelookups
说说手册：
This directive enables DNS lookups so that host names can be logged (and passed to CGIs/SSIs in REMOTE_HOST). The value Double refers to doing double-reverse DNS lookup. That is, after a reverse lookup is performed, a forward lookup is then performed on that result. At least one of the IP addresses in the forward lookup must match the original address. (In "tcpwrappers" terminology this is called PARANOID.)