Re: strange ssh performance issues

Harald Hoyer wrote:

Kevin Kempter wrote:

Hi List;

First let me say that (1) I have a fairly unusual (I suspect) ssh setup, and (2) I hate the virus known as windows

Here's the deal;

The client I'm working for uses a SonicWall firewall to control access to the data centers. Unfortunately there are issues with the Linux openVPN clients (specifically open swan) where it connects but locks

openvpn != openswan.

all other connections out of the firewall. So, until we figure this out the solution is to use the windows version of the SonicWall client. I've installed vmware and installed a copy of VirusXP (AKA Windows XP). I installed cygwin and followed the instructions here to install the ssh server: ( http://pigtail.net/LRP/printsrv/cygwin-sshd.html ) although I did not run the mkpasswd and mkgroup commands, they seemed to break the install of ssh server.

Anyway, I also setup an ssh key so I could login to the M of VirusXP without a password. Next I setup a config file in my Linux $HOME/.ssh dir with many entries like this (one for each host in the data ceners that I need to connect to):

Host dataCenterHostname
        Hostname 10.1.x.x               # data center I.P.
        HostKeyAlias 10.1.x.x          # data center I.P.

ProxyCommand /usr/local/bin/netcat-proxy-command 172.16.128.128 %h

The 172.16.128.128 I.P. addr is the I.P. of the VirusXP image within vmware via nat. (I could not make the ssh connections work via bridged networking).

The /usr/local/bin/netcat-proxy-command script is a netcat (nc) script and contains this:

#!/bin/sh
gateway=$1
internal=$2
ssh $gateway nc -w 1 $internal 22

To use this setup I boot up VirusXP, open the SonicWall VPN client and connect to one or more of the data centers. Then in Fedora 7 (the host OS) I open a terminal and run this:

ssh dataCenterHostname

so, to my issue. Most of the time this setup works fairly well, in that it does connect. It usually takes about 30 seconds for me to get a password prompt for the target data center host. This is acceptable but I think there's something weird going on that delay's the connection. I say this because I can open a cygwin windowin VirusXP and do an ssh <I.P.> and I get a password prompt immediately.

The main issue is that several times a day the connections start to take several minutes to return the password prompt. I need to restart the cygwin service in VirusXP, and sometimes that doesn't help so I reboot the VM instance of VirusXP. This is quite frustrating, however I'm a DBA and have limited networking knowledge. Does anyone have any thoughts?, suggestions?, comments?

Thanks in advance..

You may try:

Host dataCenterHostname:
        GSSAPIAuthentication no

in ~/.ssh/config

These are times I get:
08:56 [summer@numbat ~]$ time ssh school  date
Sat Oct 13 08:56:57 WST 2007

real    0m4.649s
user    0m0.020s
sys     0m0.016s
08:56 [summer@numbat ~]$ time ssh cdm date
Sat Oct 13 08:58:40 WST 2007

real    0m0.568s
user    0m0.020s
sys     0m0.017s
08:56 [summer@numbat ~]$

--

Cheers
John

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