VTP question

creamy_stew

Hello all!

I've been studying now for a couple of months to get my CCNA. I took the CCNA in 2001, but since I let it lapse, I figured it was time to get back on the horse.

First of all, just let me ask: Is it just me or does the CCNA cover a whole lot more material now? I seems it covers a lot of what used to be on the Switching exam which I studied for but never took.

Anyway, I came across this question (or something similar)

*What is the purpose of the command "vtp password mypassword"

The problem is, I think there are two feasibly correct answers:
1. It is used to validate the sources of VTP advertisements
2. It is used to prevent a newly added switch from sending unwanted vlan configuration information to other switches in the vtp domain

Thoughts:
I'm a bit unclear as to what exactly "validate the sources" in (1) means, but setting a vtp password should certainly provide some sort of validation.

If you add a switch with the same vtp domain as other switches in your network and that switch has a higher VTP revision than other switches in the network, the only thing that prevents it from propagating its unwanted vlan info is if you set a vtp password.

Since the question mentions "other switches in the vtp domain", I went with answer (2). However, the guy who wrote the test claims the answer is (1)


Any thoughts

cisco_trooper

creamy_stew wrote:

The problem is, I think there are two feasibly correct answers:
1. It is used to validate the sources of VTP advertisements
2. It is used to prevent a newly added switch from sending unwanted vlan configuration information to other switches in the vtp domain

I think option 1 includes/implies option 2.

JavonR

I would say #2 would be the best answer on a test.

To answer your first question the CCNA covers much more material now then it ever did. Due to this they came out with the CCENT to go ahead of it

jason_lunde

Ya it is a bit tricky. However, adding a new switch to the network alone will not allow it to send unwanted vlan config. information if:
1)It is not in the same domain
2)It does not have a higher revision number
3)Its password does not match that of the vtp domain

Both are feasible answers in my mind as well, however the exact purpose of the vtp password is to validate the sources of vtp advertisements.

Just my opinion though.

Met44

The purpose of the vtp password command isn't to prevent newly added switches from sending unwanted vlan config information, however it has that effect. The purpose of it is to validate the source of the advertisement.

It would also have the effect of not allowing that switch to receive vlan information, making it unable to grab the vlan database for its new network from another switches.

To prevent newly added switches from messing up your VTP domain, you would change the domain name back and forth before putting the switch on the network, in order to reset the config revision number. They are probably expecting choice 2 to match a question similar to that.

They could have thought of a better way to ask the question, but I think choice 1 is the better answer.

APA

definitely option one

If you left a switch as a VTP server or Client with a higher revision number but in the same VTP domain as the rest of your switches you can potentially wipe out your whole VLAN config...

Without the password set this rogue Server\client would not be allowed to overwrite the existing VTP config...

creamy_stew

Thanks all!

I'm still uncomfortable with this question though. If a similar question comes up in the exam, hopefully it's less ambiguous.