Switch misconfigurations

[Arusuvai Ambi]

Configure the multiple layer2 switches in any way you like so that it will pop up some error message in the console. 1 mark for each different error message.

E.g. below
%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/1 (2), with Switch FastEthernet0/1 (1).

[Giuseppe Larosa]

Hello @Arusuvai Ambi ,

to have the CDP VLAN mismatch it is enough to connect two access ports in different VLANs like 10 and 20.

Hope to help

Giuseppe

[Torbjørn]

As @Giuseppe Larosa said this is a CDP warning for having mismatched untagged VLANs on the switch. Note that this could also be caused by connecting a trunk and an accessport in a non default VLAN, or simply mismatched native vlan between two trunk interfaces.

[Georg Pauwen]

Hello,

here are a few more:

S1

interface GigabitEthernet0/0
switchport trunk encapsulation dot1q
switchport mode trunk

S2

interface GigabitEthernet0/0
switchport trunk encapsulation isl

Error:

*May 31 10:28:29.317: %SPANTREE-7-RECV_1Q_NON_TRUNK: Received 802.1Q BPDU on non trunk GigabitEthernet0/0 VLAN1.
*May 31 10:28:29.317: %SPANTREE-7-BLOCK_PORT_TYPE: Blocking GigabitEthernet0/0 on VLAN0001. Inconsistent port type.

S1

interface GigabitEthernet0/0
switchport trunk encapsulation dot1q
switchport mode trunk
switchport trunk native vlan 99

S2

interface GigabitEthernet0/0
switchport trunk encapsulation dot1q
switchport mode trunk

Error:

*May 31 10:32:04.007: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet0/0 (1), with Switch GigabitEthernet0/0 (99).

S1

interface GigabitEthernet0/0
switchport mode access

S2

interface GigabitEthernet0/0
switchport trunk encapsulation dot1q
switchport mode trunk

Error:

*May 31 10:35:02.983: %SPANTREE-7-RECV_1Q_NON_TRUNK: Received 802.1Q BPDU on non trunk GigabitEthernet0/0 VLAN1.
*May 31 10:35:02.984: %SPANTREE-7-BLOCK_PORT_TYPE: Blocking GigabitEthernet0/0 on VLAN0001. Inconsistent port type.

[MHM Cisco World]

the CDP have TLV native vlan value and this TLV is send via only trunk Port, 
so config two trunk port, each one in different SW and each one with different  native vlan 

MHM