VTP MD5 Error messages

Lessons Discussion
1

Feature VLAN:

VTP Operating Mode : Client
Maximum VLANs supported locally : 1005
Number of existing VLANs : 5
Configuration Revision : 0
MD5 digest : 0xDD 0x30 0x74 0xC9 0x0E 0xDD 0x66 0x4F
0xA6 0x7F 0xE6 0x40 0x53 0xDC 0xA6 0xAC
*** MD5 digest checksum mismatch on trunk: Fa0/43 ***
*** MD5 digest checksum mismatch on trunk: Fa0/44 ***

I changed a switch from transparent to client and received the MD5 messages above.

I tried putting the client switch back to transparent then to client mode again.

Eventually found adding a vlan on the server to force synchronization fixed the issue.

Can anyone explain what causes this problem.

Thanks

2

Hi Donald,

I’ve seen this before, usually creating/deleting a dummy VLAN on the VTP server solves it since it increased the revision number. Not sure why the switch refuses to accept the VTP update though. Next time you see this, try these debug commands:

debug sw-vlan vtp events
debug sw-vlan vtp packets

That might give us some input why the update is refused.

Rene

3

OK. I am going to see if I can make it happen again. FYI: This is a home lab.

As part of my study I am trying to find as many ways as possible to break all the

different IOS technologies to see what error messages I get then try to fix them.

Seems to work a lot better than just knowing how to configure them.

Thanks.