Filter OSPF

[drkfiber]

Hi. We have two 5300's acting as our core switches and 4108's as our distribution switches. We are running OSPF as our routing protocol. I would like it so that the OSPF link-state advertisements do not go out the end node ports(ports going out to workstations) Is the only way to do this with ACL's?

[Mohieddin Kharnoub]

Hi

you can create an ACLs for the OSPF Multicast addresses (224.0.0.5 - 224.0.0.6) and block the hello packets.

ip access-list extended "OSPF"
deny ip 224.0.0.4 0.0.0.0 0.0.0.0 255.255.255.255
deny ip 225.0.0.5 0.0.0.0 0.0.0.0 255.255.255.255
permit ip 0.0.0.0 255.255.255.255 0.0.0.0 255.255.255.255

Good Luck !!!

[OLARU Dan]

I think 4108GLs will not let you do this.

[Matt Hobbs · Accepted solution]

It sounds like you have OSPF enabled on most VLANs at the moment - I belive what you could do is disable it on the VLANs you don't want OSPF packets sent out, and enable 'redistribute connected' instead.

[drkfiber]

I enabled "ip osfp redistribute connected" and disabled ip ospf routing in the VLAN's I didn't want the ospf broadcasts in and that worked like a charm. Thanks!