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VTP question

I have 2 questions:

1)I had a scenario with 2 switches in my ICND exam. it is said that SW2 was added to the vtp domain, but the switches cannot communicate(or cannot do something vital that i dont remember right now)

and then i had the output of >show vtp status on both switches.prunning was disabled as well as VTP V2. the revision numbers were different and the number of vlans was also different.Both were in Server mode.The version of vtp was 2.i needed to choose what was the cause of this problem so i chose VTP V2 dissabled, was i right?(if VTP Version 2 is disabled there will be problems, right?)

so if i'm wrong about this what is the right answer for this...?

2)my second question is about subnets:

i had class A address block and

in the first case the mask was and in the second - and i needed to match some given addresses to their relevant case.

So, as i see it: any addresses that go like:, etc belong to mask and addresses who go like,, belong to mask - was i right?

Jagdeep Gambhir

Since both switches were is Server mode that is why they were not able to communicate with each other.

Hope that helps !



Please rate if that helps

sorry but i dont see why..

what about my other problem?

Since both switches were in a same mode that is why it can talk to each other.

In VTP domin there has to be only one server and rest should be on Client mode or transparent mode.

Your second query is not clear..please rephrase.

Please rate if helps



on every book i read it was said that a VTP domain can have as many servers as you like.


For the first part I would say that the vtp domain was different. Or could you also tell us what choices you had?

for the second part I don't see the point of the question..... a netmask could belong to any ip addresses depending on the design of your network. to be honest I don't see the point. How was the exact question? Do you remember?


1)the vtp domain was the same.

2)i dont remember the question sorry but it was something about what i wrote in 2

The answers i remember from the vtp question are:

1)vtp domain was misconfigured

2)vtp V2 mode is disabled

3)Prunning is Disabled

4)sw1(sw2 was added)was not rebooted/reloaded after the addition of sw2

5)the switches are in the same mode


The correct answer will be 1)vtp domain was misconfigured.

Explaination to others are as follows:

2) vtp mode is disabled: it is disabled by default, you only enable vtp2 if you are running with Token Ring Vlans...otherwise vtp V1 is fine.

3) Pruning is disable: again it is disabled by default, you only enable this if you want switches to automaticcaly prune vlans which are not used by that particular switch.

4) sw1 and sw2 was not rebooted after adding sw2: you do not need a reboot after adding it to vtp domain.

5) the switches are in the same mode: you can have more than one switch in Server, Client or Transparent mode. This never cause this issue.

****I know a previous poster has mentioned of having 2 vtp servers in a domain was the cause. But I disagree and I have not seen this in any documentation. I have at least 3 locations where I have more than 1 VTP servers in a domain. Works perfect for years and gives extra redundancy in case if one of them is failed.***



but the domain on both was "Tokyo" so how could that be problematic?


suppose i have sw1 with configuration revision number:1 vlans:2

sw2 has revision number:7 vlans:4

both server mode - so when i add sw2 to the domain - they cannot communicate, why?

and by the way - what happens in this situation? who send advertisements to who? what will be the final revision number and vlans number?

If the domain name is same and rev numbers are differenet on 2 different switches, the the switch with the higher rev number will over write the valn info into the switch with lower rev number. It is perfectly allowed to have 2 vtp server mode switches in the same domain. you can use any one of them to add/delet vlans and the other will be updated accordingly.

I was expecting a 6th option in your list as vtp password, which is a very common cause and i had this Question when I did my CCNA years ago. if you have a vtp password on a switch in a vtp domain, then you must have same vtp password on all other switches in that domain otherwise the switch with incorrect password does not update vtp info. This password is case sensitive too.



Thank you but sadly it isn't answering my question...

i wish i had the vtp password as a 6th answer - this answer is very obvious!

I posted an inquiry related to VLANs and listed my configuration yesterday. You might want to take a look at it. Did the test question mention anything about Trunking between the two switches? VLAN default IP addresses and default gateway addresses? Were the 2 swiches the same model or different models like 2900 series?

I hope this helps!


I don't remember but i think maybe something about a gateway though i might be confusing with different question...

i remember almost 90% was VTP related...

Well, VTP is an entirely L2 protocol (that one of its reason to be). So even if it may display an IP address in the last updater field, there is no IP influence at all on the protocol operation. So don't expect anything on this side. I think that, with the information you are remembering, I'm afraid no-one can answer the question.