Layer 3 vlan problem

[kevint21]

Hello - i have a server which sits in the dmz. Some users can connect to it and some are getting page not displayed. It looks from the firewall that users who connect successfully stay in vlan 1 as they go through the corporate network, through the firewall and into the dmz and back again. Users who fail seem to bounce from vlan 1 into vlan 80 while they are in the dmz and then the packet is dropped on the firewall.

What would cause some users to change from one vlan to another while going across a wan link (layer 3 switches)?

 

[North323]

what kind of firewall? is the firewall routing? depending on the source, the firewall is routing the return traffic to vlan 80?