DNS64/NAT64 is a transition mechanism that allows IPv6-only networks to communicate with IPv4-only servers.
How it works
- DNS64: A DNS server that synthesizes IPv6 addresses (AAAA records) for IPv4-only destinations by combining a known IPv6 prefix with the IPv4 address
- NAT64: A gateway that translates between IPv6 and IPv4 packets, allowing IPv6 clients to reach IPv4 servers
DNS64/NAT64 and WebRTC
This is particularly relevant for mobile WebRTC applications because many mobile carriers (notably T-Mobile, other LTE/5G networks) operate IPv6-only networks with DNS64/NAT64 for backward compatibility.
WebRTC challenges on DNS64/NAT64 networks include:
- STUN and TURN servers configured with only IPv4 addresses may not be reachable
- ICE candidate gathering may fail if the STUN/TURN server addresses cannot be resolved through DNS64
- Some NAT64 implementations handle UDP poorly, affecting media quality
To ensure WebRTC works on these networks, STUN and TURN servers should be configured with both IPv4 and IPv6 addresses, or developers should ensure their server hostnames have both A and AAAA DNS records.
