When telnet'ing or ftp'ing into Redhat 7.1 server it takes approx 30secs before login prompt is received. I 'think' that it is due to reverse dns lookup being active, assuming this is the case what's the best way to switch it off ? Apologies if it's a noddy question,but I'm a unix bod and some of the 'little' differences in paths, etc are catching me out on this my first Linux server

this is usually because the machine name is not in /etc/hosts

i'm having the same problem (but only on my firewall, which is slackware8 running off a cable modem and 2 nics), and here is what my /etc/hosts reads:

127.0.0.1 localhost
192.168.1.1 aya.localdomain aya

i've also suspected that it may be reverse dns lookup, but have been unable to find any sort of configuration to change in order to disable it.

any suggestions?

maybe it's not worth the trouble, since you can use ssh. but it would be nice to see what it is.

only problem is that i don't use SSH, i use telnet. :-\

i have to use telnet from work, because the firewall here doesn't support ssh connections, only telnet. cause i need to telnet into my work firewall in order to make any sort of connection outside the intranet (they're very tight on port access around here). so unfortunately, telnet is the only option to get into my network.

however, my firewall is setup to only accept connections from my machine here at work any drop any other syn packets to port 23. and any attempts to connect via ssh are sent to another machine, which has a completely different set of login credentials, so any cleartext passwords sniffed via my telnet connection are useless unless you happen to sit down at my machine here at work. so it's fairly secure. :-)

anyways, so i need to use telnet. i can live with it (and have for months now) since i'm the only one who logs in via telnet, but it's still a problem i'd like to solve.

Do you have reverse DNS for your client machine?

Cheers, but I've found the problem, someone had installed a firewall and alterted the physical ip of the box (external to the firewall was still the same) without telling anyone or altering the ip in /etc/hosts (or anywhere else).