[44net] Multicast problem?

While debugging the "suddenly lost route" that happened again at our gateway today, I stopped and restarted ampr-ripd to use the debug option, and now it suddenly no longer receives any multicast packets. I think I have read on this list or elsewhere that there is an issue with a recent glibc update or kernel update (not sure which one it was). Does anyone have details? Now ampr-ripd only works when the -r flag is passed. Without -r it sets up everything and it opens the multicast socket (which appears to work OK when looking in the trace, it is opened on the tunl0 interface), but nothing is ever received. It looks like it worked OK during the previous run, which was probably using an older glibc that was updated recently (but the system had not been rebooted). It is a Debian Wheezy system, so similar issues probably occur on the Raspberry Pi. W.r.t. the problem I was tracking: the route to 44.137.33.48/28 via 92.108.199.241 dev tunl0 has suddenly vanished at 17:00 local time (16:00 UTC), but when I looked in a wireshark dump it was appearing in the RIP broadcast. ampr-ripd did not pick it up. To trace that I recompiled ampr-ripd with debug code, started it, and then I noticed it would no longer receive ANYTHING. With -r it again receives packets and it also inserted the route to 44.137.33.48/28 again, so I am still at a loss what happened there. Rob