topic Re: Slow response with Telnet and FTP. in Operating System - Linux

Slow response with Telnet and FTP.

George Doller — Mon, 22 Dec 2003 15:28:17 GMT

Just last week we started having a problem with slow response time to get into telnet or ftp from a pc to any 1 of our 3 HP's. We've determined that if we have an entry in the host file on the HP and do a telnet or ftp 192.1.1.xxx the response comes right up. If we don't have an entry in the servers host file, it takes like 90 seconds. This just started happening last Wednesday. Before that things were fine. Everyone in systems and Networks say they didn't change anything. Has anyone experienced anything like this. Thank you

Re: Slow response with Telnet and FTP.

Olivier Drouin — Mon, 22 Dec 2003 15:37:47 GMT

Most likely someone changed the DNS settings.

Check
/etc/resolv.conf ( check if it is ok).

Check
/etc/nsswitch.conf files

You should have a line more/less like this:

hosts: files nis dns

O

Re: Slow response with Telnet and FTP.

George Doller — Mon, 22 Dec 2003 15:37:48 GMT

I posted this in Linux instead of HP by mistake, but any comments would be appreciated. Thank you

Re: Slow response with Telnet and FTP.

Olivier Drouin — Mon, 22 Dec 2003 15:38:21 GMT

I think this applies for hpux as well but I may be wrong.

Re: Slow response with Telnet and FTP.

George Doller — Mon, 22 Dec 2003 15:39:32 GMT

These files haven't changed, but thanks.

Re: Slow response with Telnet and FTP.

Olivier Drouin — Mon, 22 Dec 2003 15:48:03 GMT

Are you using NIS ?

If you do a

beetle:~$ nslookup box01

is it coming with an answer fast ??

Re: Slow response with Telnet and FTP.

Olivier Drouin — Mon, 22 Dec 2003 15:53:43 GMT

For example my

hosts entry in /etc/nsswitch.conf is:

hosts: files [NOTFOUND=continue] nis [NOTFOUND=continue] dns

if I do a nslookup on a hosts that is only resolvable by DNS it outputs like this. It takes about 1 second.

bash-2.02# nslookup nodisclose.bell.ca
Using /etc/hosts on: stan

looking up FILES
Trying NIS
Trying DNS
Non-authoritative answer:
Name: nondisclose.bell.ca
Addresses: 198.XX.XX.XX, 198.XX.XX.XX

Do you have the same behavior ?

Re: Slow response with Telnet and FTP.

Steven E. Protter — Mon, 22 Dec 2003 16:07:54 GMT

There may be less of us Linux heads but your issue is standard Unix.

The most likely cause of this on an HP box is slow DNS server response(Microsoft DNS?) or network issues on the hp box.

lanadmin -x 0

Change the number to fit your main interface.

If you don't get correct speed and duplex, consider creating a /etc/rc.config.d/hpbtlanconf file with speed and duplex hard coded in.

Don't do this with a Gigabit lan card.

SEP

Re: Slow response with Telnet and FTP.

Martin P.J. Zinser — Mon, 22 Dec 2003 16:12:36 GMT

Definitly sounds like a problem with name resolution. You system is most probably can not reverse translate the identity of the incoming host and the delay you see is the timeout of the nameresolution. What happens if you try to resolve these hosts manually?

Greetings, Martin

Re: Slow response with Telnet and FTP.

K.C. Chan — Tue, 23 Dec 2003 09:31:51 GMT

Under the assumption that your dns is functioning properly, have you make sure that your host uses dns first instead of /etc/hosts to resolve name lookup? I have not work with hpux for quite sometime, but as I remember it; it should be located in /etc/nsswitch.conf.

Re: Slow response with Telnet and FTP.

George Doller — Tue, 23 Dec 2003 09:52:05 GMT

Everything seems to be set right. I think we have a problem with the microsoft DNS. It is up and looks ok but I don't think it's doing what it should. I have the Network people looking at it.

Re: Slow response with Telnet and FTP.

Adam Moody_1 — Wed, 24 Dec 2003 05:04:28 GMT

First thing:
Are your FTP and Telnet daemons configured to do a reverse lookup for logging purposes?
Does your Linux server have the required suffix searches in resolv.conf?

It really sounds like your server cannot do a reverse lookup on the workstations, so check: resolv.conf, and that reverse lookup pointers exist on the DNS servers.

Can you do a reverse lookup on the client PC IP addresses (clear DNS cache before doing this).

I'm guessing you DNS people cleared out unwanted DNS entries for workstations thinking they're not needed anymore..

Hope this helps.
Cheers
Adam