VTP version

So, I was practicing VTP commands on my switches today and I came across some unexpected results when I typed "vtp version 1" on my 2950.

Basically, I have 3 switches connected together :

2950/3550/3550PWR

I set the 2950 to act as the "server"
The 2 3550 was set to act as the "client"
All 3 of the switches are set to the domain name of "novtp" and they are using version 2 of vtp.

Now here is the interesting thing:

As i stated above, I entered the "vtp version 1" command on the 2950 in global configuration mode BUT, only the 3550PWR changes its version to 1. Both the 2950 and the 3550 remained as 2. From what I understood in CBT Nuggets, all three of the switches supposed to have changed to version 1 when I typed in that command. When I try to type in "vtp version 1" again in the 2950 the switch tells me that "VTP mode already in V1." but "show vtp status" says otherwise, i.e the version is 2.

Other than this version thing, everything else works find. e.g if I create a new vlan in 2950, the 2 others will get it.

Any explanations would be greatly appreciated.

Find more posts tagged with

SAVE $250 on Your CISCO Boot Camp — Use Code "EXAM26"

Exclusively for TechExams members for Infosec Boot Camps starting before April 30, 2026

View CISCO Boot Camps

Comments

Monkerz

Enter "no vtp version" from global config on your server.

impz

Monkerz wrote: »

Enter "no vtp version" from global config on your server.

tried "no vtp version" got :"incomplete command"
tried "no vtp version 2" got :"VTP mode already in V1."
tried "no vtp version 1" got :"VTP mode already in V1."

Monkerz

Not too sure then. Did you manually enable V2 on the clients?

impz

Monkerz wrote: »

Not too sure then. Did you manually enable V2 on the clients?

well originally, I did manually set all of them to version 2. Then I converted the 3550 and 3550PWR to client. From the server (the 2950) I entered the vtp version 1 command and the results were as stated above i.e :

the 2950 remained at version 2
the 3550PWR turned to version 1
the 3550 remained at version 2

Greenmet29

Idk if you have odem's icnd2 book, but on page 49, there is an excerpt that says basically that the vtp version is the highest version supported by the switches software and that if v1 is enabled, it will have disabled for "vtp v2 mode". At least that is my understanding.

impz

lol, i just read page 49 and i figured that all the switches were in fact running at version one. Apparently I was looking at the wrong message.

What throw me off was that the 3550PWR had a different system message so I was looking at the wrong message.

For example :

The 2950,3550 looked like this [At all times (regardless of the version number it was using)]:

VTP Version : 2

the 3550PWR looked like this when version 1 was enabled:

VTP Version : running VTP1 (VTP2 capable)

However it looked like this when version 2 was running :

VTP Version : running VTP2

And because I didn't read the Odom book before I started to lab, I made an assumption that the vtp version being used by the switch was where the message was saying "VTP version : 2" when infact, I should have looked at "VTP v2 Mode : enabled"

thx for the help greenmet and monkerz