I have a brand new Cisco 9300 access layer switch that is trunked to a Dell Force 10 core switch. The core switch is a VTP Server for several VLANs. While the 9300 ports were configured for hosts, it was NOT a VTP client yet so it had no knowledge of our current VLAN structure. To give an example, I had a port configured "switchport access vlan 14." Once the server was brought online as an active access layer switch, it was configured as a VTP Client in our custom VTP domain. However, any device on vlan 14 cannot communicate past the 9300 switch even though the port channel tagged on the Force 10. In fact, I am simply re-using the port channel configured on the core switch to connect the trunk ports to the new 9300 switch. If I do a "show vlan" on the 9300 it shows my vlan 14 with the proper name as it is configured on the VTP server.
My question is, if a port was configured to exist on a particular VLAN before the switch was a VTP client, are there two conflicting VTP entries in the vtp.dat database on my 9300, one local and one obtained from the VTP server? It doesn't seem like this could be happening since "show vlan" looks identical to a different access layer switch that is a vtp client in the same environment.
- VTP domain name
- VTP password
- VTP version may be significant
To propagate vlans may be needed to add VLAN. One of switches need to be configured as VTP server.
Port between switches need to be configured as trunk.
Move port to transparent mode, configure VTP domain name and VTP password, version and then move VTP to client mode (procedure will reset vtp revision number).
VLAN Configuration Guide, Cisco IOS XE Everest 16.6.x (Catalyst 9300 Switches)