turn off intervlan routing for a vlan

mbrunton77 · ‎08-20-2012

I have layer3 switch with 3 vlans on it. One of the 3 vlans, I don't want to it be used for intervlan routing. So I need it not to show up as conneted in the routing. This one vlan is really just Layer 2 traffic, but since I am running DHCP for that vlan on the switch, I need to create a L3 interface. Is there a way to turn intervlan routing for a vlan?

cadet alain · ‎08-20-2012

Hi,

you'll have to configure an ACL and apply it inbound on this SVI denying IP for the other vlans subnets as destination.

Regards.

Alain

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Alessio Andreoli · ‎08-20-2012

Use the passive interface command in case of OSPF, EIGRP or IGP

https://supportforums.cisco.com/thread/30240

Alessio

andrew.butterworth · ‎08-20-2012

If your switch supports it put the VLAN in a new VRF. You will need to edit the DHCP scope on the switch but its just to add the VRF name. Other option is as cadet alain says and write some ACLs and apply them to the SVI. I'd write both inbound & outbound ACLs just to be sure. Make sure you allow BootP so DHCP continues to work - you will need to allow both broadcast & unicast for the informs it sends at half the renew time.

access-list 100 permit udp host 0.0.0.0 eq bootpc host 255.255.255.255 eq bootps

access-list 100 permit udp 10.1.1.0 0.0.0.255 eq bootpc host 10.1.1.1 eq bootps

Where 10.1.1.0/24 is the subnet and 10.1.1.1 is the SVI interface IP address.

Andy