Wyse z90 DHCP/Network loss

[Steven King]

Good morning everyone I am fighting a problem where our Wyse z90's are randomly loosing network connectivity some time through out the night. We are running the z90's with windows embedded.  and our network is 6509 core with 3750g stacks and 4507 chassis and infoblox as our DHCP.  We have gone through and turned on spanning tree on the ports connected to the Wyse clients.  Has anyone seen this before or have any ideas?

Thank you

Steven King

Also a Hard reboot of the Wyse z90 brings the network back up. 

[John Blakley]

There are a couple of things to check. Are the switches logging disconnects as the port going down when this happens? If so, that's a physical issue and you should check cabling, hardware, etc. If it's NOT logging anything like that, the dhcp server is probably not a factor in that once it gets an address, it won't try to refresh that address until it hits half-life (meaning if your lease is good for 2 weeks, it will request an update at a week), so unless you have your lease times extremely low, I wouldn't suspect it.

What do you mean by "turned on spanning tree on the ports?" Did you turn portfast on?

HTH,
John

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[Steven King]

I think we have our lease time set to 8 hours.  yes we turned portfast on.  

This morning when I checked on that had gone offline over the night the port was still showing the MAC address in the address table and I belive the port was still showing up. 

[John Blakley]

Having portfast on wouldn't cause you to get disconnected. The port is just going into forwarding faster than if portfast was disabled. So, your client will ask for the currently assigned address in four hours. Is this a consistent problem? As a test, can you statically set one of the problem clients to see if the problem goes away?

HTH,
John

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[Steven King]

Thank you John for your reply's.  Yes I can set a few of them to static address's.  It is fairly random on which ones are going to break overnight.