On Sun, Dec 03, 2017 at 04:01:35PM -0500, Scott Nicholas wrote: > I joined a VPN network (dn42) to learn BGP and such and decided to do > so with OpenBSD, which I'm also learning. Most peers are Linux > machines and they re-use their address on each VPN tunnel as a /32. I > have been successful doing the same until I decided I needed ospf for > my internal routes. > > openospfd sets the interface (identified only by its IP) as the > multicast source. Since several tunnels have that address, it sets it > incorrectly. A brief look at Linux headers show that their newer > ip_mreqn struct includes an interface index since Linux 2.2. Perhaps > this is a useful inclusion in the OpenBSD kernel so that userland can > pick the interface correctly? > > For now I've worked around this by assigning /31 aliases in > 192.168.0.0/16 to the interfaces. But I'm curious what others are > doing that use OpenBSD as a router, as it's all fairly new to me. I'm > reading that OSPF could also have unicast neighbors setup, but > OpenOSPFd doesn't have this feature.
I have also experienced the same thing and worked around it using /30s but would be nice to know how to approach this properly.
