topic Re: ssh delay about 16 seconds in Operating System - Linux

ssh delay about 16 seconds

Maaz — Tue, 12 Dec 2006 13:09:11 GMT

ssh client OS: rhel 4
ssh server OS: rhel 4

I ssh my "ssh server", it takes almost 12 seconds before getting the promt(password prompt) back.
#ssh 10.0.0.5
<12 seconds wait>
root@10.0.0.5's password:

I did 'ssh -v 10.0.0.5' and found that the cause of delay(of abt 12 secs) is "Authentication Method".

excerpt from 'ssh -v 10.0.0.5'
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: gssapi-with-mic
debug1: An invalid name was supplied
Cannot determine realm for numeric host address

debug1: An invalid name was supplied
Cannot determine realm for numeric host address

debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/identity
debug1: Trying private key: /root/.ssh/id_rsa
debug1: Trying private key: /root/.ssh/id_dsa
debug1: Next authentication method: password
root@10.0.0.5's password:

plz help
Regards

Re: ssh delay about 16 seconds

Ivan Ferreira — Tue, 12 Dec 2006 13:35:36 GMT

To identify if it's a DNS reverse lookup problem, configure:

/etc/ssh/sshd_config

UseDNS no

Re: ssh delay about 16 seconds

Ivan Ferreira — Tue, 12 Dec 2006 13:36:02 GMT

Forgot to say that you need to reload the service:

service sshd reload

Re: ssh delay about 16 seconds

Maaz — Fri, 15 Dec 2006 06:12:15 GMT

I simply comment and delay gone
GSSAPIAuthentication yes
to
#GSSAPIAuthentication yes

Thanks anyway
Regards

Re: ssh delay about 16 seconds

Andre Lejeune — Fri, 05 Jan 2007 12:12:14 GMT

I had a similar problem and disabling DNS worked.

Re: ssh delay about 16 seconds

Siert Zijl — Wed, 10 Jan 2007 19:01:56 GMT

The server is unable to resolve the IP address you are coming from.

Make sure reserve DNS is working correctly or put your source IP address and hostname in the /etc/hosts file.

If the server does resolve correctly, please check how long it takes to do the reserve DNS lookup (command: dig ipaddress).

If you don't need resolving at all, disable DNS lookups in /etc/ssh/sshd_config "UseDNS no" as others preferred before.