This message indicates that the native vlan on trunk ports or vlans on an access ports does not match on the 2 sides.
If you check your config then on int fa0/2 the access vlan is 2 but on fa0/21 I believe you have configured it for vlan 1 although this is not the complete config which you have posted from int fa0/21 but description says it is for vlan 1. Now in this case vlans are different on both the ends and both the ports are connected to each other and CDP will report this message.
If it is intentionally designed for some purpose then you can disable CDP and you will not see this message or else you can configure interface fa0/21 as an access port and assign it to vlan2 something like this
Hi, that is the complete config for port fe0/21. Both ports go into the LAN switches. I think if it's not in a VLAN it goes into VLAN 1? all I need VLAN 1 on FE 0/21 is so I can manage the switch via an IP address.
Let me know if you want the full config or if there is a better way to do this. fe0/2 I need to stay where it is.
VLAN 2 I have our and firewall inside port only and this link to the LAN.
Sorry I typed wrong port numbers in my last post. Anyways what you are doing is correct as per your description. My only concern is you are getting "Native Vlan Mismatch" message and I will like to know these ports are connected to which devices?
Fa0/1 and fa0/21 are connected to each other or some other devices?
All I can tell you as I'm not at work is that both ports connect to a huge core switch. They each go into a different vlan each. I have only got these errors since upgrading the ios, as it was 3 years old. What actually causes this native vlan error?
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