Linphone Peer to Peer Tips
Here is what I have to do for peer to peer calls (the kind I an my family and friends use the most). linphone-3.6.1
Even with direct internet connection, you must set firewall_policy=1 (Behind NAT, specify public ip) in order to make linphone use the correct ip. Otherwise, it randomly picks an ip, discarding those classified as "private" - i.e. it refuses to use a VPN.
For direct peer to peer calls, use a sip address like this:
sip:address@hidden:a40a:99bf:b885:44e4:7a3c:1577:9377]
Your default identity (used for receiving a peer to peer call) should be in the same format.
You are not expected to type these - use the handy address book.
If you need to also use linphone with a centralized SIP provider (e.g. to call an anc!
ient POTS style address - i.e. telephone number), you must use an IPv6 VPN, and set firewall_policy=2 (behind NAT, use STUN server) *after* setting the desired IPv6 public ip with firewall_policy=1. A STUN server typically only responds on IPv4, so while in IPv6 mode, linphone will fallback to firewall_policy=1 (none of this is documented). With this setup, you just need to switch to IPv4 to use the centralized SIP provider, and IPv6 to make and receive Peer to Peer calls.
This all seems very fragile. I hope that future versions give due consideration to peer to peer usage. In particular, a documented way to specify the desired "public" ip (even if it is a private VPN or local LAN ip - another common peer to peer use is as an office intercom).