Question : Inter VLAN routing Cisco 3750 apparent same config not working now.

I am so confused.  Through the console port I used the CLI to config vlan 1, vlan 10, and vlan 20 from scratch on a freshly installed/updgaded 3750.  I assigned a management IP (192.168.11.2) on vlan 1 and assigned a default gateway to the switch (192.168.11.1 our WatchGuard firewall/router).  Plugged everything in and it all worked and vlans talked to each other.  Simple as that.  To note, this worked eventhough I only assigned a management IP address to vlan 1 I never assigned a seperate subnet to vlan 10 or vlan 20.  The vlan 1 computers on my network are assigned 192.168.11 addresses, vlan 10 is on 192.168.12 and vlan 20 computers are assigned 192.168.22.  The computers on the network have default gatways that point to 11.1, 12.1, and 22.1 which are the ports on our WatchGuard Firewall.

Now the problem:  I added another 3750 and stacked them.  Because of a seperate problem I reloaded the original switch and started from scratch again but, I cofigured the stack the same way as I configured the stand-alone switch the first time.  This time around the vlans don't talk to each other.  I have researched for hours and everbody says I have to assign a seperate IP address to each vlan and then assign that as the default gateway on the corosponding computers in that vlan.

 I am confussed because I never did that the first time before the stack and it all worked just fine.  The first time I Iiteraly created vlans and added ports to them without any other configuration and it worked.  Why not now?  Is it because of the stack?  I thought they were supposed to act like on big switch in the stack.  Is it because I started using Cisco Network Assistant and it is getting it's hand involved into something?  Was it a magic router and I messed it up now?  Help Please!

Answer : Inter VLAN routing Cisco 3750 apparent same config not working now.

My comment about trunk to the Watchguard was under my apparently false assumption you had a single physical connection between the switch and the Wathguard.  It looks like you have 3 physical connections, so you can forget about trunking.

Gi3/0/13 needs to be as switch port mode access and switchport access vlan 1
Gi3/0/21 needs to be as switch port mode access and switchport access vlan 20
Gi3/0/18 needs to be as switch port mode access and switchport access vlan 10

If a comptuer is supposed to be in VLAN20, then the port it is connected to needs to be:

     switch port mode access and switchport access vlan 20