Hey guys. Heard about this a while, but finally tested it and took some video of the testing/configuration for everyone else to see. The short version is, if you have a native VLAN mismatch between switches when using 802.1Q, you can/will leak traffic between VLAN's. Makes sense and isn't really anything groundbreaking, but once you see it done it makes you think.

Let me know what you guys think. Video is posted at my blog (file is too large to post here. I did a poor job of exporting it...fairly new to using Camtasia): Native VLAN mismatch = leaked VLAN’s? | SGT CCIE