In this L2TP/IPSEC setup, the firewall rules in the interface tab do not seem to apply because of the underlying "incoming" assumption.
To log traffic from L2TP clients, I created a "pass all" FLOATING rule, interface L2TP/IPSEC, direction outgoing, all IPv4 protocols, TCP flags any, sloppy state.
That should take care of it, but TCP traffic is simply dropped. So I added a second rule specifically for TCP traffic. The rules are:
Pass&Log IPv4 * * * * * * none Secret Rule
Pass&Log IPv4 TCP * * * * * none Redundant Secret Rule
In summary:
the IPSEC interface will only log the first packet of the L2TP exchange
all the rules applying to L2TP clients seem to be enforced only in the out direction and must be enforced with a floating rule
it is not possible to drop a specific interface from the logs using an explicit block all rule.
If anybody can enlighten me, I would be grateful.
Regards,