ftp delays

Hello,

I'm having a small problem. When I try to connect to a FTP server it takes about 30 seconds for me to open the FTP connection it self. I am wondering what can cause such a long delay. Most of the people tell me that the server is not able to resolve my IP to a hostname and the people recommended me setup reverse DNS. Before I do so, my question is how come I can connect to some FTP server without any problems?

Thanks a lot.

Are these FTP server all public ones?

It does sound like the reverse DNS on the particyular one you are trying to connect to has problems. It could just be resolving against a poor DNS server compaired to the rest you are connecting to.

W

Not all ftp servers will attempt a reverse dns lookup. I'll bet that's why you can connect quickly to some of them.

Would the type of OS the user is running play any role in this?

I have two questions that may provide some clues:

  1. If you ping a fast server and a slow server what is the time difference?

  2. If you upload and/or download a sizable files to both a fast server and slow server, what is the time difference?

It may be a combination of network performance and system performance (probably mostly the later).

Just an observation really, I've noticed some real lag when a Windows (2000) client connects to a UNIX FTP server, but never when I go UNIX to UNIX no matter what flavour of UNIX O/S.

Maybe the lookup is happening from the Windows side and not (by default) with a UNIX FTP connection ? If I get chance I'll look into this some more as it bugs me too.

B