I ran into a strange problem this morning. We have a working PBR route map on a 6509 switch and a 3750 switch, each in different locations.
On both devices, the route-map is configured to match on one of multiple ACLs, then set the next hop to a directly-connected IP address, like so:
match ip address ACL1
match ip address ACL2
match ip address ACL20
set ip next-hop 184.108.40.206
When copying in the ACL contents for "ACL20", they were accidentally copied in to the ACL1 list, and ACL20 was never created.
Shortly after this was done, the next hop router went unreachable in both locations. Pings failed and the 6509 and 3750 each lost the EIGRP adjacency to the 220.127.116.11 router. After troubleshooting, I removed "match ip address ACL20" and connectivity returned.
My question is...if a PBR route-map tries to match on a non-existent ACL, what happens? Does it mark the next hop unreachable (even though it's directly connected) or does it match for ALL traffic and send *everything* there (thus, making it appear unreachable, as if a broadcast storm was happening)?
For Policy-Based Routing - If no traffic is matched it will simply be processed/forwarded normally by looking at the routing table or with cef. However it is possible to blackhole traffic IF the traffic is matched and the next-hop is not correct.
My apologies for giving you incorrect information Andy, Vasilis is absolutely correct. I was not aware of this sort of implicit permit for a non-existent access-list. Thank you for teaching me something new Vasilis
Thank you for the answer. It seems odd to me that it would work that way - typically, for an ACL that used for filtering purposes, if a non-existent one is applied to an interface, then it would block everything by default. My original thought was that using a non-existent ACL would simply not match and move on to the next ACL.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...