VLAN Trunking Protocol

Mode	Versions	Forward VTP MSG	Sync VLAN-DB	Modify VLANs in VTP Domain	Modify Local VLANs
server	1, 2	Yes	Yes	Yes	none
primary server	3	Yes	Yes	Yes	none
secondary server	3	Yes	Yes	No	none
client	1, 2, 3	Yes	Yes	No	Yes
transparent	1, 2, 3	Yes	No	No	Yes
off	3	No	No	No	Yes

Notes: To forward VTP msg (vlan datebase), transparent-switch must join the same VTP domain. Unles its domain is NULL (default setting).

Reset Reversion Number of A Switch to 0

SW1(config)#vtp mode transparent                 //Method 1: change to transparent mode
SW1(config)#vtp domain <unsued-domain-name>      //Method 2: change to an unused domain

Troubleshoot VTP Propagation Failures

1. VTP information only passes through a trunk port.
2. Make sure that if EtherChannels are created between two switches, only Layer 2 EtherChannels propagate VLAN information.
3. Make sure that the VLANs are active in all the devices.
4. One of the switches must be the VTP server in a VTP domain.
5. The VTP domain name must match and it is case sensitive.
6. Make sure that no password is set between the server and client, or the same on both sides.
7. Every switch in the VTP domain must use the same VTP version.
8. Switches that operate in transparent mode drop VTP advertisements if they are not in the same VTP domain.
9. The extended-range VLANs are not propagated.
10. The Security Association Identifier (SAID) values must be unique.
11. The updates from a VTP server do not get updated on a client if the client already has a higher VTP revision number.