Cisco VTP – Impact of Removing VTP from a Production Network

You can see the primary server (if any) in the output of show vtp status:

Primary ID                        : 0011.2233.4455
Primary Description               : primary-switch-name

If the Primary ID is 0000.0000.0000, then your current switch does not recognize any primary server, including itself. To answer your questions:

1. When you try to promote a switch to the VTP primary server role, VTP performs a sanity check to make sure no other switch on the network if already the primary, and will warn you if one is found. Either way, IOS will prompt you to proceed, so you can still back out if you're unsure. This is important, because the new primary server will cause all other VTP clients and servers to overwrite their existing VTP configuration with that of the new server. However, only switches in the same VTP domain and with the same password would be affected, and you would be able to see those with show vtp devices.

2. I think you have it mostly correct. The one part I would comment on is that the only time a primary server demotes itself to secondary status is when it rejoins the VTP domain after a reload. During normal operation, a primary server will remain the primary server unless you run vtp primary on another server.

If you have only one switch configured as the VTP server, and it is not primary, I would conclude that it was rebooted at some point, which would have caused it to demote itself. It should be safe to promote it back to primary. If you're ever unsure, back up your VLAN database (typically flash:vlan.dat on smaller platforms) before making changes, so you can switch to transparent mode and restore your VLANs quickly if you need to.

Cisco has a comprehensive document on VTP Version 3 that goes over all of this and more.

Based on @TeunVink's comments, Problem 1 was fixed.

Below are the methods I have used for setting up the management interface.

I chose not to use VLAN 1 for management, as per many recommendations. So I cleared IPs from VLAN 1 and Management Console (Fastethernet0), as:

conf t
int vlan 1
no ip address
exit
int fa0
no ip address
exit

Assuming that VTP is enabled is working between Core and Access switches:

Create a separate management vlan in the core switch. E.g. VLAN 10

conf t
vlan 10
name management
exit

Assign IP address to this vlan

int vlan 10
ip address 10.0.10.1 255.255.255.0
exit

Then connect to the 2960 access switch via console and verify the vlan 10 is present there using show vlan command. It should be there as the VTP already would have taken care of distributing it. Now assign ip separately here for vlan 10 in the access switch as:

conf t
int vlan 10
ip address 10.0.10.2 255.255.255.0
exit

Configure ssh by following this link.

That's it. Now Ping 10.0.10.2 from other vlans to the Access switch. Should be good to go.

This link can be treated as an excellent reference for this purpose.