switch blocking ip address?

[bopritchard]

i have a client workstation (nt 4.0) that will on occassion lose all ability to communicate through my switch (model 6509)...i can do a loopback ping fine...but i can't reach anything else...in my lan or not...as soon as i reserve that ip address on my dhcp server and force the machine to pick up a NEW ip address...it works fine....for a time, that is.....then it goes right back to the same behaviour

thought the workstation nic was maybe bad for a while...so i replaced the machine...no good...same deal

what in the world is happening

 

[bebop1065]

Post the switch's config. Maybe someone smart will happen by.

http://soulphoto.net

CCNA student

 

[gunthnp]

is it on the same vlan it sounds like its not fowarding dhcp request or syns

gunthnp from

http://wwww.advancedigitalsolutions.com

 

[inetworku]

have you configured portfast on the switch port? If you show logging on the 6509 does it show the port throwing off any errors? Are there any other errors occuring on the port interface, such as drops?

 

[vipergg]

Occasionally clients that go into power save or standby will cause a problem , try disabling these to see if that helps at all .

 

[Ru55ell]

Disable Spanning tree protocol on the switch port for that device. I know you did not mention you are seing this issue at reboot but I know this is an issue with STP. STP is not needed for ports attached to end stations. It is designed for switch to switch connections. PCs are getting so fast on bootup they are requesting network addresses before the switch initializes Ethernet. I'm looking for a link at Cisco.com but cannot find it.

 

[NetEng631]

You may have a bad port on the switch. Try plugging it into a different port. If you dont have a different port call Cisco TAC. If you have a service contract they will over night you a new switch or card.

NetEng

 

[damesac]

What is the size of the network? Are you aware of all your machines? Is the user receiving any "ip address conflict" error messages? It could be that another machine on the network (or someone is bringing in an outside machine) is configured with that same address and is kicking your client offline.

"Be the packet."

 

[lui3]

It sounds like a conflict to me as well. I have seen these types of issues with nics not reporting the conflict to the user and disabling the tcp/ip stack. depends on the nic driver.