I think question title is self-explanatory, but I can re-iterate.
I have just recently got annoyed enough at my own dedicated server's FTP connection delay to go hunting for what causes delay.
"Perpetrator" was IdentLookups configuration option. It defaults to on, thus causing noticeable delay on connection attempt. When switched off, connections are done instantly.
So, my question is: what's intended use of indent lookups? Not just in context of FTP server, but in general? Most firewalls block ident probes, so I don't see the point...
Somebody to enlighten me, please? :)