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ssh slow

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unicks
Advisor

ssh slow

Running on a BL860c, 11.23.
When I try to ssh from my server to another server it takes over a minute before getting a prompt on the other server. Telnet works okay.
I've checked /etc/resolv.conf, /etc/hosts, /etc/inetd.conf and they look okay, compared to a server that works. I checked the syslog.log file, no errors.

Anyone have any ideas where to look?

Thanks

nj
6 REPLIES
Grayh
Trusted Contributor

Re: ssh slow

Steven E. Protter
Exalted Contributor

Re: ssh slow

Shalom,

Try by numeric ip address. If its still slow, look at lanadmin, network and switch configuration.

If numeric if fast and name is not, then you may have slow DNS servers, or DNS servers from Microsoft that need a patch or two or three.

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Steven E Protter
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unicks
Advisor

Re: ssh slow

Grayh - Thanks, but I have other servers with the same ssh_prng_cmds file and there's no issue with them. It's just this one server.

Steven - Thanks, you got me going in a positive direction. When I use the IP address it does go faster, almost immediate. But, I'm pointing to the same DNS server as the other servers that work ok. But it dose seem to be related to reverse lookup. I have an entry in my hosts file and nsswitch.conf looks at the hosts file first, then DNS.

And I'm getting ready to leave for the night, so thanks for the responses and I'll take this up in the AM. Points will be coming.

Thanks,

nj
OldSchool
Honored Contributor

Re: ssh slow

check all the dns / hosts stuff on the destination that you are trying to ssh into. I'll bet you will find an issue with the name lookup of the originating host.


in otherwords: SvrA -> ssh -> SvrB, given you're description, trying to lookup SvrA on SvrB has problems....
Bill Hassell
Honored Contributor
Solution

Re: ssh slow

> When I use the IP address it does go faster, almost immediate.

...indicating that DNS isn't working correctly on this server.

> But, I'm pointing to the same DNS server as the other servers that work ok.

Use nsquery rather than nslookup. You may be pointing to the same DNS servers but the first couple of servers may not be reachable or the DNS server refuses to talk to this system. For exapmple:

nsquery hosts some_host

> But it dose seem to be related to reverse lookup. I have an entry in my hosts file and nsswitch.conf looks at the hosts file first, then DNS.

...reverse lookup -- very common mistake in Microsoft DNS servers. You can eliminate the delay using your current nsswitch.conf file by adding each hostname (and aliases such as FQDN's) to your /etc/hosts file.

nsquery hosts 12.34.56.78

to show reverese lookup results.


Bill Hassell, sysadmin
unicks
Advisor

Re: ssh slow

Thanks for the help folks, I apologize for the delay in assigning points, I got sent out of town. I haven't nailed this down 100% yet, but will, with the direction you pointed in.

Thanks again,

U