It is extremely easy to accidentally blow away your VTP database, so be sure that you set a VTP domain that is not the default so a switch that happens to have a high revision number does not take over and replace your huge VTP tree with one of its own.You can't manually force updates because VTP configs are pushed based on the highest current VLAN database revision number.
Those VLANs should now be created on SW1, and SW1 should have sent VTP messages, one for each VLAN change, to SW2. The new VLANs have propagated to all switches in the topology, and the configuration revision number (3) matches on all three switches. We will change SW2 to transparent mode and the VTP domain to PACKETPUSHERS. If VTP version 2 in transparent mode does not inspect the domain name, then SW3 should get the new VLANs, and its configuration revision number should match SW1. SW2: SW2#conf t SW2(config)#vtp mode transparent SW2(config)#vtp domain PACKETPUSHERS SW2(config)# SW2(config)#end SW2# SW1: SW1#conf t SW1(config)#vlan 40 SW1(config-vlan)#vlan 50 SW1(config-vlan)#vlan 60 SW1(config-vlan)#end SW1# With those configuration changes complete, let’s verify and see what our VLAN databases look like now.
SW2 should, in turn, forward the VTP messages to SW3. From this output, we can see the VLANs have been created on SW1, but they do not exist on SW2 or SW3.
VTP advertisements are sent every 5 minutes by default, or when there is a change in configuration revision number caused by the addition or deletion of a VLAN on a server.
Server Mode – In VTP server mode you can create, modify and delete vlans.
For VTP to begin functioning the participating switches must be configured with the same VTP domain name. Switches running VTP can be configured for three different modes: server, client, and transparent.
A switch with VTP enabled is in server mode by default.Tasks to perform: N/W 10.1.10.0/24 for Students (VLAN 10) N/W 10.1.20.0/24 for Trainers (VLAN 20) N/W 10.1.50.0/24 for Servers (VLAN 50) N/W 10.1.100.0/24 for Marketing (VLAN 100) N/W 10.1.200.0/24 for Management (VLAN 200) Step 1: Configure VLANs on the VTP server only. Step 3: After completing the first two steps, check with show VLAN command on server and clients to verify your configuration.Note: VTP advertisements are flooded throughout the intenseschool domain every five minutes or whenever a change occurs in VLAN configurations.The documentation clearly states that in VTP version 2 a switch in transparent mode will not inspect the domain name, but we can see from this test that it does appear to inspect the domain name and does not pass along messages that do not match its configured domain name. I will configure the same domain name on SW2, but leave it in transparent mode. Before you start configuring something in production or on a lab exam, be sure you know how it really works.I recently replaced the switch that was functioning as the VLAN server for the rest of the network.The old VLANs are all working fine -- it is just not receiving new ones.