Spanning Tree errors: %SPANTREE-7-RECV_1Q_NON_TRUNK and SPANTREE-7-BLOCK_PORT_TYPE

[ivanka_busta]

Hello,

I have a cisco WS-C2950T-24. There was a Cisco router connected to ports 23 and 24 which have the following configuration:

interface FastEthernet0/23
description VoIP 
switchport access vlan 21
no ip address
duplex full
speed 100
service-policy input QoS
mls qos trust dscp
storm-control broadcast level 5.00 2.00
storm-control action trap
no cdp enable
spanning-tree portfast trunk
end

interface FastEthernet0/24
description Data 
switchport access vlan 323
no ip address
duplex full
speed 100
service-policy input QoS
mls qos trust dscp
storm-control broadcast level 5.00 2.00
storm-control action trap
no cdp enable
end

Port 23 is used for the voice vlan and 24 is for the Data vlan.

We were trying to replace the Cisco router for a new Teldat router. However, when we connected it we got the following logging messages:

000136: Nov 10 13:50:07 CET: %SPANTREE-7-RECV_1Q_NON_TRUNK: Received 802.1Q BPDU on non trunk FastEthernet0/23 VLAN0021.
000137: Nov 10 13:50:07 CET: %SPANTREE-7-BLOCK_PORT_TYPE: Blocking FastEthernet0/23 on VLAN0021. Inconsistent port type.
000139: Nov 10 13:50:50 CET: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/23 on VLAN0021. Port consistency restored

After getting these messages when we issued the show int status command instead of getting this:

Fa0/23  VoIP        connected    21           full    100 10/100BaseTX

We got this:

Fa0/23  VoIP        connected    trunk           full    100 10/100BaseTX

I think that is very strange because port 23 is configured as an access port for vlan 21 and then it automatically changed to trunk.

What could be the problem: wrong configuration on switch, on router, both? Thanks in advance.

[Mark Malone]

Hey you shouldnt have this on an access port spanning-tree portfast trunk remove the trunk part should only be spanning-tree portfast if its true access port with 1 vlan  

[Evgeny Khorokhorin]

Hi,

You should configure fa0/23 to only mode access by command "switchport mode access". Also if you don't expect BPDU packets on interfaces I advice you to add these lines:

spanning-tree portfast (trunk)
spanning-tree bpdufilter enable
spanning-tree bpduguard disable