Getting started with Elastic SIP Trunking

Alex_Sberna — Thu, 27 Nov 2025 11:48:05 GMT

To get started, you must have an account set up on the Sinch Build Dashboard.

Note: The following guide is generic and does not cover all configurations necessary for setting up a specific device (PBX, SBC, UCaaS, etc.). For specific integration guides, view the following guides found here.

All Elastic SIP Trunking and Numbers operations can be found under their respective sections on the lefthand navigation menu of the Sinch Build Dashboard.

A Sinch Elastic SIP Trunk consists of two primary elements— the SIP Trunk itself, where the Trunk’s name and domain are configured, and one or more SIP Devices which will contain the IP/Port and Transport options to connect with your IP PBX or Application.

Configure your IP Allowlist

The Sinch Elastic SIP Trunking platform will send your calls from the following IP Addresses. Please allow these IPs in your network’s IP Allowlist:

SIP:
- 206.146.131.0/28
- 206.146.133.0/28
- 206.146.134.0/28
- 206.146.136.0/28
- 206.146.137.0/28
- 206.146.138.0/28
- 206.146.139.0/28
- 206.146.141.0/28
Media:
- 206.146.131.128/26
- 206.146.133.128/26
- 206.146.134.128/26
- 206.146.136.128/26
- 206.146.137.128/26
- 206.146.138.128/26
- 206.146.139.128/26
- 206.146.141.128/26

Non-encrypted SIP traffic from the Sinch Elastic SIP Trunking network will be sent from port 5060. SIP calls encrypted with TLS will be sent from port 5061. For media we will use UDP ports 10,000-60,000.

SIP Trunk technical specifications

Within your IP-PBX or SIP Application make sure your SIP Trunk is configured with the following settings.

CODECs: G.711 μ-law (aka G711u, G711MU or PCMU) & G.711 A-law (aka PCMA or G711A)
DTMF – RFC 2833/4733 with payload type 101
Privacy header – Sinch Elastic SIP Trunking is designed around the use of P-Asserted-ID for the passing of privacy and STIR/Shaken information. However, we will also send Remote-Party-ID on calls inbound to location.

Next steps

Now you can learn how to create your first SIP trunk.

You can also check out Elastic SIP Trunking release notes to see new enhancements.

article Getting started with Elastic SIP Trunking in Elastic SIP Trunking

Getting started with Elastic SIP Trunking

Configure your IP Allowlist

SIP Trunk technical specifications

Next steps