cat 3750 with vlans cant interoperate with a switch that dont have 802.1q

Unanswered Question
Jul 9th, 2009


i have a issue, i configurated a 3750 witch vlans 10 (pc), 20(servers) 30(wireless). the intervlan routing works just fine. but i have a server that is connected to a switch non admin, so dont have the 802.1q option,and that generic switch is connected to a port in the vlan 20 of the 3750. i cant ping to that server in any situation like other server in the same vlan... the only way that i can ping to that server is if the port that is connected to the other generic switch is in the vlan 1 (without tagging) in the 3750, any idea to fix that problem ?

the same situation happens when i change the generic switch and put a cat500 (all port are int he vlan 1 by default), if the packcet is tagging the cat500 wont switch the packet ?

I have this problem too.
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milan.kulik Fri, 07/10/2009 - 00:10


if your generic switch is not supporting 802.1q at all, just connect it to an access port belonging to VLAN20 on your 3750.

You should be able to Ping your server from any port within VLAN20.

Your symptoms look like the port on your 3750 still belongs to VLAN1 (default). I'd check that port configuration (switchport access VLAN 20, switchport mode access, trunk nonegotiation, etc.).

If you want to Ping it from another VLAN, you need a correct routing between that VLAN and VLAN20 (correct default gateway on your server, e.g.).




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