Routing between VLANs and non-VLANs on 3550

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Sep 30th, 2007
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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.

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Jon Marshall Sun, 09/30/2007 - 22:45
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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 Sun, 09/30/2007 - 22:50
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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 Mon, 10/01/2007 - 01:34
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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 Mon, 10/01/2007 - 16:43
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Thanks for the help, that got it going. Cheers.

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