We have a CCR-1072, with version 6.45.8.
We have several IPIP tunnels configured.
One of the tunnels is behaving strange. In order to debug it we tried to sniff packets.
When we start the sniffer the traffic of the IPIP goes to 0.
We think that the problem is related to Fast path.
In the IPIP tunnel Fast path is enabled by default.
If we disable Fast Path the traffic goes to 0.
What can be the reason for that.
Impossible to tell without seeing actual config.
My guess: firewall rules. For fast-tracked traffic one needs two matching firewall rules such as these two:
add action=fast-track connection-state=established,related <other selection criteria>
add action=accept connection-state=established,related,untracked <other selection criteria>
When sniffing packets, fast-track is disabled. And if there isn’t a firewall rule allowing packets that would otherwise be fast-tracked, connections get dropped. Selection criteria in the “action=accept” rule don’t necessarily have to be identical to those in fast-track rule, but if they aren’t they should be less restrictive, i.e. they should pass all traffic fast-tracked.
Connection tracking is disabled, so I think that “fast-track” is not possible.
My issue is with “fast-path”, which seems to be a different thing.
The router also has OSPF, MPLS and VPLS if that matters.