I have a quagga router with two transit neighbors and announcing my own IP space. I recently joined a public peering exchange (IXP) and so I'm part of their local network (/24), together with all other participants. So far everything works fine.
Now for security I wonder if other participants could not simply route all their outgoing traffic through me? For example what happens if any other participant would point a default route to my IXP ip. If I understand correctly all outgoing traffic from that participant would then go to my router which would route it to the internet using my transit uplink, right?
So I wonder if I have to take any measures against it. My ideas are:
Setup firewall (iptables) rules so that only traffic with a destination of my own IP space is accepted from other IXP participant. Drop any other traffic from IXP participants.
Somehow make quagga use a different kernel routing table for each neighbor (or peer-group). The routing table for the IXP neighbors would not contain any entries except for my own IP space and so no routing using my ip transit uplinks would occur. Looking at the output of
ip rule showshows quagga is not doing this automatically?
Am I on the right track? Why is 2. not implemented in Quagga directly? How do hardware routers (cisco, juniper, ..) deal with this problem?