Good explanation. I've always tried to specifically avoid using OpenDNS on my OBIs, after reading
OBI's Google Voice FAQ. It's nice to now see the reason why.
Apart from VOIP, I am a big fan of OpenDNS and employ it in various scenarios. Google's Public DNS (8.8.8.8 and 8.8.4.4) as well as the ancient 4.2.2.2 Public DNS are good alternatives, and I use these for the OBIs. But I still prefer OpenDNS in other non-VoIP setups.
Thank you both for the info,
pc44