> From [email protected] Fri Dec 9 > 13:42:59 2016 > From: Erik Lax <[email protected]> > Subject: Proxy ARP and npppd (tun) > To: [email protected] > Date: Fri, 9 Dec 2016 19:42:46 +0100 > > Hi, > > In previous OpenBSD versions (5.9 and eariler) it was possible to do > proxy-arp with the npppd server if the proxy-arp was setup before the > npppd connection was made. As of 6.0 (and todays snapshots) proxy arp > and npppd (tun interfaces) seems to be broken. > > The behavior is now as such; > > - if an proxy arp entry exists (on a given interface), then incoming > packets will be sent out again on the same interface (instead of > forwarded to the tun interface) > > Setup. > > 1. Adding the proxy-arp entry 10.2.50.123 (the npppd/tun0 client ip) > > arp -s 10.2.50.123 00:50:51:b2:e4:c1 permanent pub > > 2. Connect the client, send ping to host on em0, incoming icmp replys > are sent out on em0 again instead of tun0 > > A quirk? > > If the arp entry is deleted (arp -d 10.2.50.124) on the openbsd host, it > starts to work temporarily (the packet is forwarded to the tun > interface) but only because the remote host has an arp cache. > > Is there an other way of doing this? > > Regards > Erik > >
I encountered a similar problem recently. I had remembered npppd working from long ago and thought it must work around the problem somehow. I didn't realize npppd/proxy ARP was broken. I was able to solve my problem with a package called arpd. Since its ARP responses don't make it into the routing table, it worked for me. I wasn't using npppd though. Martin
