Wednesday, October 1, 2014

prevent vlan's of communicating with eachother


Setup: Cisco router with multiple VLAN's configured on it.
How can you prevent 2 VLAN's communicating with eachother? Normally I would do this with ACL's like this:
access-list 102 deny ip 1.1.1.0 0.0.0.255 2.2.2.0 0.0.0.255
access-list 102 deny ip 2.2.2.0 0.0.0.255 1.1.1.0 0.0.0.255

int vlan 1
ip address 1.1.1.1 255.255.255.0
access-group 102 in

int vlan 2
ip address 2.2.2.2 255.255.255.0
access-group 102 in
 
This however is not handy when dealing with lot's of VLAN's configured on a router. Any suggestions of tweaking this or using an alternative to improve scalability?