Some of my XS4ALL (KPN) IPTV channels stopped workking properly. The started to stutter, normally an indication of trouble at multicast subscriptions. Looking at the logfile (while the little one was trying to watch BabyTV) I found the culprit:
The source address 220.127.116.11 for group 18.104.22.168, is not in any valid net for upstream VIF. This address is part of a multicast block 22.214.171.124/16 assigned to KPN.
Adding this new network to file:/usr/local/etc/igmpproxy.conf using the
altnet 126.96.36.199/16 made it all work again.