Hi there,

I have a computer on my network that other users have noted is very slow for some network operations. If another computer attempts to do something with something on one of it's NFS shared file systems it take several times longer than another simular computer. I have spent ages looking on the web for a program that can test the speed of and diagnose network connections. So far I have found loads of nice things but none that quite do what I am looking for. Does anyone know and can recommend software that test LAN network speeds between linux and other Unix computers, please? One that could also give diagnostics as to where to look for the problems too would be really good.

Thanks

Paul`

Paul,

I don't know of a program that will do this without some expertise on your part. In troubleshooting network issues you will need either hardware or software that can capture packets off the network. If you have a Solaris or SGI box they both have a program named 'snoop' that will do this. There also is a program named 'tcpdump' that has been ported to many OS's that will do it. I have supported NFS since the late 80's and the problem you are describing is quite often because of dropped packets. If you are using NFS over UDP then if one packet of a multi-packet reply is dropped all the packets have to be retransmitted. This is why a network problem will be affect NFS before other apps. You can often set NFS to use TCP (the default for some ports) and this will 'hide' the problem and your performance will increase. However you still won't have addressed the real problem, you will just be using a transport protocol that handles problems better. Sorry I can't give you a complete solution but hope this is of some help.

Dan

speedguide.net has a tcp/ip analizer that may be able to help.

Thank you both for your sugestions.

I have moved the computer to a new location and I cannot duplicate the problems. I think there may be a bad cable or port where the computer was before.

Thanks

Paul