Issue with several 2950 switches

D0nprintup_2 · ‎07-01-2009

I have several 2950 switches connected in a chain. On the first one I have a dhcp server and everything is in 1 vlan.

on port 24 I have an uplink to switch 2. On switch 2 i have an uplink to 3. All ports are confiugred the same.

My problem is any pc plugged into switch 2 will not get dhcp.

If i do a sh-mac-address-table add , I see what port its on. If i log into switch one and do a sh mac-address-table it will not show the pc.

Now if i take that same pc and plug it into switch 3 or 4 or 5. and do a show mac-address-table I see it on all the switches like i should. Also, that PC will get a dhcp address.

I cannot figure out why it isnt working on switch 2. But all other switches behind #2 work and the traffic is passing fine.

any ideas?

glen.grant · ‎07-01-2009

Make sure portfast is on for all user ports on switch 2 . that would be the only reason they couldn't pull an address if they are all in the same vlan .

D0nprintup_2 · ‎07-01-2009

ya all switches 1 - 5 are config the same why for pc ports

switchport protected

then span portfast is set

mahmoodmkl · ‎07-01-2009

Hi,

remove the switchport protected option and u will be fine.

Thanks

Mahmood

D0nprintup_2 · ‎07-01-2009

originally all the uplinks between each switch was on Gi01. It was configured with trunk (there are 2 vlans) and port fast.

Well after doing a sh cdp nei I noticed the #2 switch was connecting to switch1 on Fa0/20. That had switchport protect on it.

I removed it ont hat port now all pc's on switch2 are working.

My questions is, with it on, I know what it does but wouldnt it affect all other switches too. Since the uplink to sw1 was on it. It pasted all other switches but its own.

cool