How to route VLAN traffic to the Internet

[Cooky]

I set up a small lab at home, making sure everything will work when this gets implemented on the company's live network.

I've set up inter-vlan routing on a Cisco c3560 switch, following the instruction here
step by step.
Inter-vlan routing works fine, but the local traffic from VLAN's can't get to the Internet via my DLink NAT router.

I think that's because my DLink router can only translate one particular private IP subnet. (192.168.1.x in my case) If that's the case then we should be fine cause I can simply put multiple nat and global statements on our Pix firewall (it's our NAT device)

Anyone think it's something else that's causing the problem?

 

[spidey07]

you'll need a default route, pointing to your dlink gateway.

on the switch...

ip route 0.0.0.0 0.0.0.0 <ip of dlink>

 

[Cooky]

Thanks for the reply, spidey.
I already had the default route pointing to my DLink router.
ip route 0.0.0.0 0.0.0.0 192.168.1.1

I configured one of the ports of the 3560 as a router port (no switchport), and assigned 192.168.1.2 to it.
In fact, I can get to the Internet from the 3560 itself through the console, but not from any of the other VLAN's configured on it.

I suspect that's because none of my VLAN's are in the 192.168.1.x subnet, which is the only network that my DLink can translate traffic for...not sure if that makes sense to you guys...

 

[nightowl]

The problem that you are running into is that the Dlink does not know that the networks on your 3560 exist. All that it knows of is the 192.168x.x/24 network that is directly connected. To get it to work, in addition to the default route on the 3560, you need routes on the Dlink pointing back to the IP address of the routed port that contain the networks that you have set up on the switch.


Edit: That would work in normal situations, but like you mentioned Cooky, I am not sure how the Dlink does NAT and if it will do it for any traffic or just the local subnet. If the latter is the case you will need NAT on the switch to get it to work and am pretty sure that it is not supported on the 3560 (but that is not to say that it is not in the code 😉 ).