Here's my scenario:
I have a PIX 515E with Interface 4 going into my DMZ VLAN which is on my 3750 stack. I've created a guest vlan in my stack and a vlan interface on the pix off of interface 4. This vlan interface is 4.12. I understand I need to trunk the port on my switch to see the vlan's on this interface. Here's what I've put:
switchport trunk encapsulate dot1q
switchport mode trunk
switchport trunk allowed vlan 12,15
However when i do this i can't get a reponse back. Can someone help?