SIP trunk providers for SessionPBX

SessionPBX works with your own SIP trunk. Your carrier supplies the phone numbers, outbound calling and caller ID, and bills you for them. SessionPBX supplies the phone system. SessionTalk doesn’t sell trunks or numbers.

Each guide below shows the settings for one carrier, on the carrier’s side and in the SessionPBX Add SIP trunk wizard.

About these guides. The carrier settings were checked against each carrier’s published documentation on 19 October 2026. The SessionPBX field names come from the product. Carriers change their platforms, so if your carrier’s portal shows a different value, use theirs.

UK carriers

International carriers

More guides: SignalWire, Gamma, Voiceflex, registration-based carriers and any other carrier.

How SessionPBX connects to a carrier

On Call Routing > SIP trunks > Add trunk, a five-step wizard asks for:

1. Provider: a name and a template. Twilio, Telnyx, SignalWire and Plivo have their own templates and can read your account. Other carriers use Generic carrier (IP authentication), Generic carrier (username and password) or Generic carrier (registration).
2. Connection: the carrier’s Host, Port (default 5060), Transport (UDP, TCP or TLS) and Direction (both directions, inbound only or outbound only).
3. Authentication: By our IP address, with the carrier’s signalling addresses listed under Carrier IP addresses, or Username and password, with Register to this carrier on by default. Registration is supported over UDP. TLS registration isn’t available yet.
4. Inbound: your numbers in international format, such as +442071234567, and whether to Refuse unknown numbers.
5. Outbound: the Caller ID to present, Assert caller ID in (From header, P-Asserted-Identity or Remote-Party-ID), Outbound number rules and Additional gateways.

Some carriers send incoming calls to an address but authenticate outbound calls with a password. For those, the guides use two trunks: an inbound-only trunk that recognises the carrier’s IP addresses, and an outbound-only trunk with the carrier’s username and password. Turn Register to this carrier off on the outbound trunk, and list your numbers on the inbound trunk only.

What carriers need to know about SessionPBX

• Incoming calls: SessionPBX accepts calls from carriers on UDP port 5060 or TLS port 5061. TCP isn’t accepted for incoming calls. SessionPBX has no SRV or IPv6 records, so carriers should use the hostname or IP address and port.
• Called number: the carrier must put the dialled number in the Request-URI, in international format, with or without the +. National formats, such as 02071234567, don’t match.
• Outgoing calls: SessionPBX can reach the carrier over UDP, TCP or TLS on any port.
• Caller ID: sent in the From header, and optionally also in P-Asserted-Identity or Remote-Party-ID.
• DTMF: RFC 2833 telephone events.
• More than one trunk: outbound calls use the trunk whose Outbound number rules prefix matches the dialled number most closely, then the lowest priority. A trunk with no rules carries every call. If a trunk fails, calls don’t move to another trunk, but they do move between the gateways listed on one trunk. For a backup gateway, use priority 10: a lower number wins, and the main host is priority 0.

If you’re not sure which region your workspace is in, email support@sessiontalk.co.uk.

See also Connect a SIP Trunk and Phone Numbers & Outbound Calls.