How to delete VLAN in a VTP server?

By reading books, I got the impression that deleting vlan.dat would delete all the vlans. It doesn't. The command "del vlan.dat" only deletes the vlan.dat file in the flash. All vlans are still active. If I reload the server switch, somehow the switch would grab all the vlan information from a VTP client switch and all the vlans are restored.

So I have to delete vlans one by one on the VTP server switch using command "no vlan 10", "no vlan 20", "no vlan 30", etc. Is there a faster way to delete all vlans on a VTP server and propagate that information to all VTP client switches?

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canoj

Under global config:

no vlan 2-4094

iamme4eva

workfrom925 wrote: »

If I reload the server switch, somehow the switch would grab all the vlan information from a VTP client switch and all the vlans are restored.

The somehow is how VTP works. A switch will always overwrite it's own database if it receives a VTP advertisement with a higher revision number, regardless of whether it is a client or a server.

pamccabe

You could change the mode to transparent and then delete the vlan.dat. I haven't tried this but it's an idea.

iamme4eva

pamccabe wrote: »

You could change the mode to transparent and then delete the vlan.dat. I haven't tried this but it's an idea.

That would work. However, as soon as you changed it back to server or client mode, it would pull the VLAN's back from any VTP server that advertised, unless you set a different domain name first. You can't propagate a blank VLAN database, because it would have a config revision of 1, which would be immediately overwritten by any advertisement with a higher revision.

pamccabe

Good point. I guess then canoj would be correct because that should increase the revision number and be advertised.

NetworkVeteran

iamme4eva wrote: »

The somehow is how VTP works.

Yup. Servers and clients behave the same from a protocol perspective. It's only the user interface that differs.

theodoxa

The Boson ExSim-Max (Practice ICND2 Exams) caught me on that. I was under the [incorrect] impression that a VTP Client would not update a VTP Server. It will. The terminology is confusing. The only real difference between the two is that you cannot create or delete VLANs on a VTP Client [while it is configured in Client Mode]. But, if it already has them configured...

workfrom925

theodoxa wrote: »

The Boson ExSim-Max (Practice ICND2 Exams) caught me on that. I was under the [incorrect] impression that a VTP Client would not update a VTP Server. It will. The terminology is confusing. The only real difference between the two is that you cannot create or delete VLANs on a VTP Client [while it is configured in Client Mode]. But, if it already has them configured...

You are right. When I read the book from Cisco NetAcad, it gives me the impression that client doesn't pass any vlan info to the server. But it does. I saw it happen in my home lab. I just don't find an easy way to delete vlans. Finally I pulled the trunk cable and delete the vlan on each switch. I finally realize VTP doesn't work well and why Cisco is doing away with VTP in the new CCNA curriculum.

NetworkVeteran

workfrom925 wrote: »

I just don't find an easy way to delete vlans. Finally I pulled the trunk cable and delete the vlan on each switch. I finally realize VTP doesn't work well and why Cisco is doing away with VTP in the new CCNA curriculum.

This was more about your not understanding how the protocol works than any inherent flaw.

"no vlan 1-4094" - job done! (this would be a rare network-wide operation)

xXErebuS

iamme4eva wrote: »

The somehow is how VTP works. A switch will always overwrite it's own database if it receives a VTP advertisement with a higher revision number, regardless of whether it is a client or a server.

Popped in here after responding to your other thread that you didn't state you were using VTP. I replied in other thread already but this is correct.

Samo3411

Hello

do you want delete them only from the vtp server or from all the switches ?? if you want to delete them from all the switches just delete the vlans on the server (one by one not Vlan.dat file ), if you want just to delete whats in the vtp server change the mode to transparent delete them and keep it in transparent mode and choose another switch to be the server....