noob: 2960 all ports defaulted to trunk, connectivity lost when changed

[michaely360]

Hi,

I have a 2960 which I am using to learn IOS. I recently upgraded the IOS to 15.x and managed to restore the config back to factory settings as it was previously in production.

I created a new VLAN, so there are now two; default and vlan10.

I assigned interfaces 0/10 - 0/13 to vlan10 and set their mode as access ports, the remaining interfaces show in vlan1.

Nothing is plugged into any interface, except interface 0/4, which is connected to my network for the purposes of telnet for me to manage.

When I run "show interfaces status", I see 0/4 showing as status = connected, Vlan = trunk, etc

When I run "show interfaces trunk", I see 0/4 showing as mode = auto, status = trunking, native vlan = 1, vlans allowed on port = 1-4094m etc

I don't want any of the ports on my switch to act as a trunk. I don't need any routing between vlan1 and vlan10.

So, if I run "interface gigabitEthernet 0/4" then "switchport mode access" I lose connection to the switch. I have to go plug my network cable into another interface to regain management.

I'm obviously missing something. Why do I lose connectivity when changing a port from trunking to access? And how can I set all ports to access if I don't need routing between vlans?

Best regards

Michael.

[Iulian Vaideanu]

What does "connected to my network" mean about interface 0/4?  I mean, what exactly is it connected to (another switch port, a server / computer network interface)?

Whatever it is, it's most likely configured as trunk, so when you change 0/4 to access you should also change its "neighbor" to access...

[michaely360]

Thanks for the reply.

Interface 0/4 is connected to another switch (another 2960 in fact) and my computer is plugged into that 2nd switch.

If I plug my computer directly into the switch I am trying to manage I can indeed change a port to access port and continue using it.

I understand this now. No doubt I'll be back later with more questions.

Thanks.