Routing between VLANs and non-VLANs on 3550

bamcandee · ‎09-30-2007

This may seem like a silly question, but..

I currently have a Cisco 3550, running IOS 12.1(20)EA1, which supports inter-VLAN routing. Basically I want to set up a VLAN for one section of the network, and leave the rest of the network as is. I want to be able to route between the VLAN and the rest of the network. Once this is going, I will use ACLs to limit traffic between them.

There is one port of the 3550 which is a member of the VLAN(for the server), the other members of the VLAN are on a 2950 switch, trunked to the 3550. They can ping the server and each other, but not the rest of the network, and vice versa. The rest of the ports on the 3550 aren't VLANed. The router cant route between the two networks because there isnt an IP for the non-VLANed network on the router. Is there any "interface" I can bind an IP to for all the non-VLANed ports on the switch, without having to VLAN them and the rest of the network into a seperate VLAN.

I have successfully done this before with the setup running a switch with a seperate router, using subinterfaces.

Thanks.

Jon Marshall · ‎09-30-2007

Hi

"The rest of the ports on the 3550 aren't VLANed"

They will be in vlan 1 if you have not explicitly set up a different vlan for them so you should just be able to create a Layer 3 SVI for vlan 1 and as long as "ip routing" is enabled on the 3550 it should work fine.

interface vlan 1

ip address x.x.x.x

no shut

HTH

Jon

Jon Marshall · ‎09-30-2007

Forgot to add

The only other possibility if the ports are not showing as being in a vlan is if they have been made routed ports ie.

int fa0/1

no switchport

This would mean fa0/1 would not show up in a "sh vlan" output. To revert back to a switchport

int fa0/1

switchport

Jon

Nicholas Poole · ‎10-01-2007

Your hosts on VLAN1 will need to have their default gateway set as the IP address of VLAN1, or alternatively if they are using a different default gateway then that router will require a static route to the new VLAN subnet on the 3550 and vice-versa.

bamcandee · ‎10-01-2007

Thanks for the help, that got it going. Cheers.