The PhoneNet core voice network now supports IPv6 for SIP and IAX. If your switch or device has IPv6 connectivity, it can now connect to our core nodes over IPv6.

IPv4 access continues to operate as before. You do not need to change your configuration.

Benefits for Mobile Users

Many mobile carriers now supply IPv6-only services. Your phone gets an IPv6 address but no IPv4 address. To reach an IPv4-only server, the carrier translates the traffic with NAT64 or 464XLAT.

This translation is a common cause of problems with voice calls:

• SIP messages contain IP addresses in the headers and in the SDP body. The translation gateway does not change these addresses. The far end can receive an address that it cannot reach. This causes one-way audio, no audio, or calls that do not connect.
• All IPv4 traffic goes through the carrier’s translation gateway. If the gateway is a long distance from you, this adds latency to your calls.

When your phone connects to PhoneNet over IPv6, there is no translation gateway in the path. The addresses in the SIP messages are the real addresses of your phone and of PhoneNet, and the audio can take a more direct path.

If your softphone connects through one of our SBCs, you will get these benefits when IPv6 is enabled on the SBCs.

Benefits for Office Code Holders

Mobile networks are not the only services that share IPv4 addresses. Some fixed wireless, satellite, and fixed-line ISPs put their customers behind carrier-grade NAT (CGNAT) for IPv4, but give each customer a public IPv6 prefix.

If your switch is on one of these services, IPv6 gives it a direct path to PhoneNet with no NAT between them.

Session Border Controllers

Only our Asterisk nodes have been IPv6 enabled. If you have a service that connects via one of our Session Border Controllers (SBCs) then it will remain on IPv4 only for now.

We plan on enabling IPv6 support on our SBCs soon and will post a further update once done.

Before You Use IPv6

IPv6 networks do not normally use NAT, so each device on your network can have a public address. Make sure that your firewall only allows the traffic that your switch or device needs. For example, SIP, IAX (UDP port 4569), and your RTP port range.

Some switches and softphones need a configuration change before they use IPv6. Refer to the documentation for your system.

If you have problems connecting over IPv6, contact tech support or ask for help in the #phonenet-help channel in our Discord server.