SIP Trunking

MessageBird SIP Trunking offers you the possibility to place outbound voice calls from your VoIP platform to phones anywhere in the world. It is currently not possible to SIP-register with MessageBird.

A SIP-trunk makes calls via the public internet or a private IP-connection. Our SIP-trunks run authentication protocols on your IP-addresses and/or a username-password combination. You can learn how to set up accepting inbound SIP-calls below.

How to set up SIP trunking :

To start making outbound calls, you need to authenticate your VoIP platform. The easiest way to do so is by adding the IP-address of your VoIP platform or creating an account in our Dashboard.

When you are logged in, click on 'Voice' icon in the left-panel menu and select SIP Trunking.

You can now fill in your details in just two steps.

1: Add an ACL (Access Control List)

The first step is to create an Access Control List (ACL). An ACL is used to define which IP-addresses and/or username-password accounts are allowed to use yours. To manage the authentication of your VoIP infrastructure, you can create multiple ACLs, each with one or more accounts.

On the top menu, click on the 'Access Control' tab → 'Add New' button.

Name each ACL in a new pop-up window so you can easily recognize them.

After saving the ACL, it will appear in the overview.

When you click the ACL name, you will see a new screen where you can add IP-addresses and/or username-password accounts. The options are:

  • IP-address

  • Username/password

  • IP-address and a combination of username/password

    • Important: If you have entered both an IP-address and a username/password, both need to be used in the SIP-INVITE header.

Below you find an example of a FROM field as part of SIP-INVITE header with username 31000000:

SIP from address: sip:31000000@[yourdomain];transport=UDP

2: Add a Subdomain

The second step is to create a subdomain. A subdomain is a personal DNS name inside the domain, for example, Only calls to this specific subdomain will be authenticated by the attached ACL’s.

To add a subdomain, in the top menu, click on the 'SIP Trunks' tab → 'Add New' button.

You will see a pop-up screen where you can insert your subdomain name.

The field 'Domain' is the address used for your SIP-communication. A valid domain name contains:

  • Minimum of 1 character

  • Valid characters range from 0-9, a-z and A-Z

After creating a Domain, you can attach an ACL to this Domain by selecting the domain in the left-hand menu and clicking on 'Attach Access Control List'. You can choose the preferred ACL to attach to this domain in a pop-up window.

Select the right ACL and save your choice. On the SIP Trunks page, you’ll find an overview of the ACLs attached to this particular domain.

Please take note :

  • A domain can have multiple attached ACLs

  • An ACL can be attached to multiple domains

Now you are ready to place calls from your VoIP platform to our SIP servers. Please be aware that only accounts attached to this domain can place calls. Therefore the full domain name should be used in the SIP-INVITE header. Below is an example of a SIP-INVITE header:


Localisation (optional)

For customers that require localised SIP trunking we are available in 3 regions: Asia, Europe, US.

By using the default configuration of [your_domain] your traffic will be forwarded to our European servers. In the case of a local failure the traffic could potentially be redirected to the other available regions. To be able to keep your traffic bound to one region and avoid an additional hop through our European servers, you can configure the domain name as follows:


  • [your_domain]

  • [your_domain]


  • [your_domain]

  • [your_domain]


  • [your_domain]

  • [your_domain]

By using these subdomains inter-region failover is not guaranteed.

For more details about our publicly available list of SIP server IPs visit the article: SIP Server connection details.

Find out about five reasons to use MessageBird SIP Trunking in our Blog.

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