Hello,
To use Kamailio as an outbound edge proxy you have to compile in STUN support (which in turn makes the Kamailio core dependent on OpenSSL). It'd be good if the STUN code could be moved into a module (similar to TLS) for the next major release.
This might also be a good route to take for some other things optionally compiled into core with "exotic" dependencies like SCTP.
Regards,
Peter