VTP question

Hi I've got Catalyst based network looks like this:

SW1 ----ge----- SW2 ----ge----- SW3

SW1 is in VTP-Domain called 'localvtp', server mode SW2 is in VTP-Transparent SW3 is in VTP-Domain called 'localvtp', server mode

SW1 and SW3 has diffrent VLANs database, will SW2 transport VTP frames between SW1 and SW3 ? My goal is to SW2 should filter VTP frames. I've same VTP Domains at SW1 and SW3 and SW2 is only transporting 4 VLANs between SW1 and SW3. How I can gain this effect ?

All switches are Cisco Catalyst 3750 running Cisco IOS 12.2(25)SED.

Thanks, Robert

Reply to
Robert Hass
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VTP transparent mode causes a switch to pass VTP messages, but not b affected by them. You still can create, delete and modify VLANs in thi mode, but the information configured on the switch will not propagat via VTP. VTP mode and domain information is saved in NVRAM. Transparen mode is the only mode you can use to create extended-range VLANs. The have SW1 and SW3 use different VTP databases, you will need to hav different vtp domains on each switch

-- faris

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My understanding with VTP Transparent is that it will forward VTP VLAN database information just fine, it just ignores updates for its own database. That means that SW1 and SW3 will update each others VLAN databases when either makes a changes since the domain's are the same name (assuming you don't have any auth that is different for the two).

I would think to filter VTP you need to have some sort of true layer 3 devices between your layer 2 devices to really stop VTP completely or you run a separate VTP domain for each switch.

- Ed

Reply to
Ed Horley

Check if the switch in question supports VTP off mode

set vtp mode off

Option for No VTP - Enables a switch to not only be a non-participant in VTP, but also to drop all VTP traffic (unlike Transparent mode which passes VTP traffic) thus creating a VTP boundary.

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