Connect Vonage SIP trunk to SessionPBX

Vonage SIP Trunking, part of the Vonage Communications APIs, supplies UK and international numbers and outbound calling. Vonage sends incoming calls to a SIP address and authenticates outbound calls with a username and password, so in SessionPBX you add two trunks: one that receives Vonage’s calls and one that sends your outbound calls.

You bring your own Vonage account, numbers and caller ID. SessionPBX doesn’t supply Vonage service.

About this guide. The Vonage settings on this page were checked against Vonage’s published documentation on 19 October 2026. The SessionPBX field names come from the Add SIP trunk wizard in the product. If Vonage shows a different value in your account, use theirs.

Before you start

In the Vonage developer dashboard, open Build > Voice > SIP and create a trunk. Vonage gives the trunk a domain, plus a username and password for digest authentication. Note:

• The trunk’s domain, for example yourcompany
• The digest username and password
• The Vonage numbers you’ll use

Vonage’s regional endpoints for outbound calls are:

Vonage accepts UDP or TCP on port 5060, and TLS on port 5061.

SessionPBX addresses for Vonage

Give Vonage the address for the region your workspace is hosted in. If you’re not sure which region that is, email support@sessiontalk.co.uk.

SessionPBX accepts calls from carriers on UDP port 5060 or TLS port 5061. TCP isn’t accepted for incoming calls. Calls that SessionPBX sends to Vonage can use UDP, TCP or TLS on whatever port Vonage specifies.

Part 1: Inbound calls

In Vonage: send calls to SessionPBX

1. On the trunk’s settings page, open Inbound Calling.
2. Add a SIP URI with your region’s hostname, for example uk.sip.sessiontalk.io. Choose UDP, or TLS to use port 5061. Leave SRTP off.
3. Select the SIP region nearest your SessionPBX region.
4. Link your Vonage numbers to the trunk.

In SessionPBX: add the inbound trunk

1. Open the SessionPBX project, select Call Routing, and on SIP trunks select Add trunk.

2. Provider: name it Vonage inbound and choose Generic carrier (IP authentication).

3. Connection: set Host to your Vonage endpoint, for example yourcompany.sip-eu.vonage.com. Set Transport to the one you chose in Vonage and Direction to Inbound only.

4. Authentication: keep By our IP address. Under Carrier IP addresses, add the Vonage subnets that Vonage recommends allowing for SIP:

   216.147.0.0/18
   168.100.64.0/18

5. Inbound: list your Vonage numbers in international format, for example +447700900000. List your numbers on this inbound trunk only. Don’t add them to the outbound trunk: a number listed on two trunks belongs only to the trunk saved last.

6. Select Create trunk.

Part 2: Outbound calls

1. On SIP trunks, select Add trunk again.
2. Provider: name it Vonage outbound and choose Generic carrier (username and password).
3. Connection: set Host to your Vonage endpoint for the region nearest you, for example yourcompany.sip-eu.vonage.com. Use port 5060 with UDP, or port 5061 with TLS. Set Direction to Outbound only.
4. Authentication: choose Username and password and enter the trunk’s digest username and password. Leave Auth realm and From domain blank.
5. Turn Register to this carrier off. Vonage authenticates each call, not a registration. Register to this carrier is on by default for Username and password, so check that it shows off before you continue. Leave Inbound numbers empty on this trunk. Your numbers belong on the inbound trunk only.
6. Outbound: set Caller ID to one of your Vonage numbers in international format. Vonage reads the caller ID from the From header, so leave Assert caller ID in on From header only.
7. Select Create trunk.

Vonage passwords must be 12 to 64 characters, with at least one digit, one lower-case and one upper-case letter.

Route your numbers

On Call Routing, use Inbound number routing to choose where each number rings: everyone, a team member, a ring group, a call queue or a call flow. See Phone Numbers & Outbound Calls.

Allow members to call out

Outbound calling is off for new members. Open Team Members, edit the member, turn on Outbound PSTN under Access & features, and select Save member.

Members can dial numbers in international format, such as +447700900123. SessionPBX sends the number to Vonage in international format.

Test the trunk

1. Call one of your Vonage numbers from an outside phone and check that the right destination rings.
2. With Outbound PSTN on for one member, call a public number. Check that audio works both ways and that the called phone shows the caller ID you expect.
3. If you call into an IVR, check that key presses work. SessionPBX sends and receives key presses as RFC 2833 telephone events.

If calls fail, email support@sessiontalk.co.uk with the time of the call, the number you called from and the number you called.

Sources

• Vonage: SIP technical details 
• Vonage: SIP Dashboard 
• Vonage: Which IP addresses should I allow when using Communication APIs and SIP Trunking?