Spanning Tree Issue With WAN Uplink

Hi all:

We recently purchased a secondary internet connection which has just been installed. We were given a set of 5 static IPs. The connection is provided to us via a normal patch cable just past the fiber demarc.

Connecting a laptop to said patch cable with the LAN interface set with one of the static IPs provided works fine - device can get to internet.

To test, I created a vlan to handle this traffic and assigned said vlan a port on our core switch as an access port. I then assigned the same vlan to an adjacent port connected to the same laptop to test, but was unable to get to internet.

Long story short, I ended up getting it working by disabling spanning tree on that newly created vlan. The core was reporting that it was receiving BPDU on the non-trunked port the new connection was plugged into, so it was blocking traffic on the VLAN I assigned. Here's the relevant messages from our switch (vlan 505 is the vlan I created, 3/40 is the interface the new connection is on):

Nov 28 18:56:54.694: %SPANTREE-7-RECV_1Q_NON_TRUNK: Received 802.1Q BPDU on non trunk GigabitEthernet3/40 VLAN505.

Nov 28 18:56:54.694: %SPANTREE-7-BLOCK_PORT_TYPE: Blocking GigabitEthernet3/40 on VLAN0505. Inconsistent port type.

Obviously, I'd prefer not to disable STP on the entire vlan - is there something I'm missing?