ssh / PuTTy / stupid network issue maybe?

[Paul Condren]

Afternoon all.

Ive got 3 servers all with ssh installed and were using PuTTy ssh client to connect.

We seem to have a slow network issue and as usual its up to the admins to prove it before the network monkeys get their fingers out.

Sympoms are that PuTTy connects initaly and displays a using username "joeBloggs" than we have to wai up to 5 mins before a password is connected.

The GPS consle connection is fine - quick as it should be.

Ive check routing eitc and cant see any errors. Is there a tool I can install to find out where the delay is?

I'm concerned it could be the server being slow to respond. All the patches etc are up to date and its an RP3440.

thanks

[Steven E. Protter]

Shalom Paul,

First, the network monkeys remark is over the top, but quite humorous.

I'd check if there is a significant difference in connect time between numeric ip address ssh and hostname ssh.

If there is its probably a DNS problem. You should make sure /etc/resolv.conf is correct and nsswitch.conf is configured correctly.

Also, strong random number generator for HP-UX seems to speed up ssh connects. There is a significant amount of math going on during these connects.

You could run tcpdump or ethereal to sniff the network and try and get an idea where the slow response is.

SEP

[Jesús Couto Fandiño]

Just firing an arrow in the dark...

Can you see if you can do a reverse lookup of the IP of the machine you are connecting from in the servers? I had similar problems once with telnet. The servers may be doing a reverse lookup to get the hostname of the originating computer.

[Paul Condren]

He he. I was refering to the network pople working here, rather than the general network community. No offence intended. Honest :o)

I'll give that tcp dump a go. Not sure if ssh is the bottleneck, as ive just reverted bastille so I can use telnet and that just as sluggish. The console is using telnet all the time and thats instant as I would expect.

Wiedest thing is that once your connected its all OK. Its just the initial connection.

thanks

[Tom Ward_1 · Accepted solution]

Hello Paul,

As others stated, check DNS -- both ends. See that you can resolve PC to host and host to PC.

You can try adding an entry to the servers /etc/hosts file for the PC. Provided you have /etc/nsswitch.conf set with files first then dns you can work around a DNS probem with the hosts file entry. If that works it's a DNS problem.

Good Luck,
Tom

[Paul Condren]

Sorted thanks. It was DNS to blame. I renamed etc/nsswitch.conf and resolv.conf and everything then worked.

After some more digging etc i found that our DNS servers wered configured in the firewall. D'oh.