Hello,

I have been doing some tests with kamailio and IPv6. 

My initial setup was IPv6 only and now am I extending it to a dual-stack environment. Well, and now I am starting to face some (interesting) challenges.

So, the first step in the dual-stack environment was to install RTP Proxy and configured kamailio to use it.  With this setup, the UAs locally registered were able to communicate with each-other no matter with address family (IPv4/IPv6) they were using. So far so good.

But now I want to extend my tests a bit more ... I want to communicate with the "outside world" (using ENUM and domain based SIP URIs). Do I have a way to know if the "destination" is IPv4 or IPv6? Because I need that information in order to properly bridge the calls on rtpproxy. 

I tried to use the onsend_route but it didn't work. I mean, I am able to know if the "next-hop" is IPv6 or IPv4 but it seems that it is "too late" to use rtpproxy. BTW ... I am assuming that if the "next-hop" is IPv6 then the final user agent will also be IPv6 (the same for IPv4) 

Should I use some other approach? For example, failure route instead? 
Does anyone have a similiar setup? How are you solving this issue?