[Linphone-developers] wrong NAT keep alive method over udp

[Philip Morant]

Hi,

I'm running linphone version 3.9.1-1231-gecda7e6 on Ubuntu, configured
to use UDP (through NAT).

I read in https://tools.ietf.org/html/rfc5626#section-4.4.1 that keep
alive with CRLF
" MUST only be used with connection oriented transports
   such as TCP or SCTP; it MUST NOT be used with connection-less
   transports such as UDP "
yet when I wireshark my calls (which abort roughly one in every 4
calls) I find that linphone is sending double CRLF keepalives over
UDP.

The code in static int send_keep_alive(belle_sip_channel_t* obj) in
listeningpoint.c appears to confirm this, since it sends a double CRLF
regardless of what transport is in use.

Please confirm / deny this analysis.

Thanks !

Philip