[SR-Users] IPv4, IPv6, RTPProxy and Kamailio

[Klaus Darilion]

On 03.12.2013 14:23, Mark Zeman wrote:
> Hello all,
>
> The subject says most of it, I think.
>
> We set up our Kamailio and RTPProxy according to
> http://kb.asipto.com/kamailio:kamailio-mixed-ipv4-ipv6
> with the addition of an alias (siplab.ch), and the DNS to go with it, as
> well as TLS and SRTP.
>
> However, we only get working calls IPv4-IPv4 and IPv6-IPv6! IPv4-IPv6 we
> get a proper connection,
> secured with SRTP, but no audio. Looking at the network, RTP packets go
> from the caller to the server,
> but nothing leaves the server and no RTP packets go from callee to server.
>
> Do you have any idea how to fix this?

Before fixing you need to find the problem. Probably the SDP get 
rewritten incorrect. To debug this issue, you have to inspect the ip 
address and ports in the received and sent SDPs if they are correct 
(e.g. IPv4 and IPv6 address of the rtpproxy).

You mentioned TLS - thus it is difficult to inspect the raw SIP packets. 
Is such cases you can either:
- adding lots of xlog("$mb, ...") to your config and watch syslog
- use the sipcapture module to write every incoming and outgoing SIP 
message to the DB, and analyze the packets in the DB
- Disable TLS. Use TCP. If it fails with TCP it will also fail with TLS. 
Once it works over TCP, it will also work over TLS.
- If you really have a problem with TLS only, you could enable the NULL 
cipher to have a unencrypted TLS connection, or use Wireshark's TLS 
decoding capabilities
- Configure rtpproxy to communicate via UDP socket instead TCP socket. 
Then you can also capture the communication between Kamailio and rtpproxy.

It seems you just call the rtpproxy functions with some wrong flags. 
Make sure properly detect the direction (4to6 or 6to4) an set the i and 
e flags accordingly.

regards
Klaus