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New Member

Trouble Getting IP from DHCP Server through 2950 swtich

I am having intermittent but becoming more regular issues with some Win98 workstations aquiring an IP address from an NT DHCP server. The suspect workstations are all going through 2950 ports on various different switches. The workstation error is 'No Domain Present...". If I cancel and then do an IP Release and Renew I wil eventually aquire an IP address but strangly enough it is always the same address on any given workstation.

HELP!!!!

Marc Share

IT DIrector LA /OC Weekly

4 REPLIES
New Member

Re: Trouble Getting IP from DHCP Server through 2950 swtich

Marc,

Have you set the switch port for 'portfast'?

conf t

int fa0/20

spanning-tree portfast

If so could you cut and paste conf and ver info?

New Member

Re: Trouble Getting IP from DHCP Server through 2950 swtich

No It is not set for' portfast' The Microsoft site states it could be related to Auto Broadcast being on. I will try the portfast setting

New Member

Re: Trouble Getting IP from DHCP Server through 2950 swtich

The symptom you are describing is normally seen with MS 95 and 98 client, the IP stack and DHCP negotiation is started on the client before the switch port has a chance to complete the blocking/listening/learning phases and does not forward the packet since it is not in forwarding state. On some switches (4000/5000/6000) you may also need to disable trunking and channeling (negotiation) since these add additional time prior to port forwarding state. As for the client getting the exact same IP all the time, this is normal dhcp behavior since the client tries to renew the address that it had last time (saves on some dhcp negotiations).

Regards,

Paul

New Member

Re: Trouble Getting IP from DHCP Server through 2950 swtich

Depending on your network configuration it maybe worthwhile adding the ip helper-address statement and pointing it to your dhcp server. There is a command on the edge switches (I think) that you can say which is your dhcp server

good luck

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