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Connect Plivo SIP trunk (Zentrunk) to SessionPBX

Plivo’s SIP trunking service, Zentrunk, supplies numbers in many countries, including the UK and US, and outbound calling. Zentrunk doesn’t use registration: it recognises your phone system by IP address or by username and password. SessionPBX has a Plivo template that uses IP authentication, and can read your Plivo account to fill in your numbers.

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

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

Before you start

In the Plivo console, under Zentrunk:

  1. Create an IP access control list containing your region’s SessionPBX IP address from the table below.
  2. Create an outbound trunk that uses that list. Plivo gives the trunk its own termination domain, such as <trunk id>.zt.plivo.com. Note it.
  3. Create an origination URI pointing at your region’s SessionPBX hostname, for example uk.sip.sessiontalk.io.
  4. Create an inbound trunk with that URI as its primary URI, and assign your Plivo numbers to it.

Note your Auth ID and Auth token from the console overview if you want SessionPBX to read your numbers.

SessionPBX addresses for Plivo

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

RegionHostnameIP address
Londonuk.sip.sessiontalk.io206.189.121.32
New Yorkus.sip.sessiontalk.io134.122.14.236
Singaporeasia.sip.sessiontalk.io152.42.251.112

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 Plivo can use UDP, TCP or TLS on whatever port Plivo specifies.

Add the trunk in SessionPBX

  1. Open the SessionPBX project and select Call Routing.

  2. On SIP trunks, select Add trunk.

  3. Provider: name the trunk and choose Plivo. To read your account, enter the Auth ID and Auth token under Connect your Plivo account and select Connect account. SessionPBX lists your numbers.

  4. Connection: set Host to your outbound trunk’s termination domain. Port 5060 and UDP are filled in. Leave Direction on Both directions.

  5. Authentication: keep By our IP address. Under Carrier IP addresses, list Plivo’s Zentrunk signalling ranges, one per line:

    13.52.9.0/25
216.120.187.128/26
18.214.109.128/25
18.215.142.0/26
204.89.148.128/26
3.120.121.128/26
18.228.70.64/26
13.238.202.192/26

  6. Inbound: your numbers are listed if you connected the account. Otherwise enter them in international format, for example +442071234567.

  7. Outbound: set Caller ID to a Plivo number. Plivo rejects outbound calls with a caller ID that isn’t a Plivo number on your account.

  8. Select Create trunk.

Using a username and password for outbound calls

Zentrunk outbound trunks can use credentials instead of, or as well as, the IP access control list. To use credentials, add two SessionPBX trunks: keep the one above with Direction set to Inbound only, and add a second with Generic carrier (username and password), the termination domain as Host, your Zentrunk credentials, Register to this carrier turned off (it’s on by default for Username and password), no inbound numbers, and Direction set to Outbound only. Keep your numbers on the first trunk only.

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 Plivo in international format.

Test the trunk

  1. Call one of your Plivo 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

Last updated on
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