Devices dropping off network

[londint]

I have just recently configured and concluded adding a 2950 to the network of a series of 6500 and 4000. When I added a device onto the 2950, it received an IP Address via DHCP and worked well. But when I added an IBM Blade Server onto the 2950, we started having devices dropping off the network. SO I had to take it of.

There is trunking configured between the 2950 and the 6500 and portfast is disabled and the spantree is ieee on both. The ports on the 2950 to which the laptop and Blade server are connected is portfast disabled.

What can be causing this and how can I rectify this?

Please note that when the IBM Blade server was conned straight to the 6509 there was no problem and it is working fine as of now but as soon as I put it on the 2950, devices start dropping off the network. What is the problem and how can I solve it?

Thanks for your help.

[zspalding]

I had a similar problem in September. The problem was being caused by the mac address of a station being removed from the mac address table of the switch. To correct the issue grab the latest IOS.

[arto.oltaci]

Take a look at the loggin on the 2950, to see if the switch interfaces are going up/down when you see the devices disappearing. Perhaps you have a auto-negotiation problem - specify the port setting duplex/speed on the server and switchport.

If you are having issues with DHCP, it could be that your IBM server may have DHCP enabled, giving out incorrect (or default) addresses, causing your other devices to appear to be dropping off.

Sniffers can be useful to drill down the scope of your problem... Ethereal is a freeware one you can use and it works quite well!