Bandwidth SIP Trunk

  • Published on Jun 2, 2025
  • 4 minute(s) read
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Overview

This guide provides step-by-step instructions for creating a realm, generating Bandwidth SIP credentials, adding a trunk profile, and configuring trunk settings for users. Each section is designed to help you set up and manage your SIP trunk efficiently.

Creating a Realm

The realm serves as both an FQDN with an SRV record and the domain to connect to for the call. To create it, use the following steps:

  1. Log into the Bandwidth Dashboard.

  2. In the top navigation bar, click Account and select SIP Credentials.


    Note

    Note: If you do not see the SIP Credentials tab, reach out to your Account Manager to enable this feature for your account. Not sure who your Account Manager is? Open a ticket with your Bandwidth Support Team or call (855) 864-7776.

  3. Scroll down to the Manage Realms section and click Add.


  4. Give your realm a name and an optional description, and then click Add. As you type, would see a preview of what the completed realm domain would look like.

    Note: The Realm field supports only lowercase alphanumeric characters [a-z, 0-9]. If this is your first realm, check the Set as Default box (you can set a different realm as default later, if you would like). Although there can only be one default realm at a time, you may use any of the realms you’ve created to complete calls.


    Once created, you can use this realm to see what IPs you would interact with for your SIP trunking. In Windows, this can be accomplished with the nslookup command in a command prompt by setting your type to SRV and using the format: sip.udp.{realm_FQDN}.

    Note

    Note: If using a different protocol, like TLS, use the prefix sips.tcp. instead.



    Note

    When performing SIP OPTIONS, you should use the server host name or ipv4 address of the server you are sending the request to. Creating SIP Credentials

Creating SIP Credentials

Now that you have a realm and the IPs your system will need to interact with, you are ready to create credentials for the caller to enter into their phone client. To do this, use the following steps:

  1. Navigate to the SIP Credentials section and click Add. 


  2. Add one set of credentials or import a bunch all at once.

    Note

    You can also do this programmatically via API using the SIP credentials endpoint.

To add one set of credentials, do the following:

  1. Enter a username and password. If you wish to generate the hashes for the username/password combo yourself, leave the Username and Password fields blank and click Supply Your Own Hashes to complete additional fields.

  2. Select a realm from the Realm drop-down menu.

  3. If you are using HTTP or programmable voice, you can also select a voice application you want to associate with this user from the Associate Application drop-down menu.

  4. Once you are finished, click Add SIP Credentials.

Note: You cannot change the username once it has been created, however, you can update the password, realm, and voice application.

Adding Trunk Profile

Once Bandwidth’s realm (SIP trunk domain) and SIP credentials are configured, the following procedures must be performed to add Trunk Profile:

  1. Log in to the ConnecttoTeams Service Portal.

  2. From Trunks, select Profiles.

    The SIP Trunk Profiles page displays.


  3. Click the Add Trunk Profile button.

    The Add Trunk Profile page displays.


  4. In the Available Voice Routes drop-down menu, select one of your already-configured voice routes.

  5. In the Trunk Type drop-down, select SIP Registration.

  6. In the Description field, enter any descriptive text for the trunk profile.

  7. In the Outbound Transport Type drop-down, select any of the following:

  • UDP

  • TCP

  • UDP/TCP

  1. In the DNS Lookup Type drop-down, select SRV.

  2. In the Outbound Proxy and Port field, enter the SIP server’s IP Address and port number.

  3. In the Emergency Outbound Proxy and Port field, enter if configured on the trunk side. This is optional.

  4. In the Codecs field, select the codecs in order of your preferences.

  5. Mark the Enforce Codecs on Inbound checkbox if you want to limit codecs on inbound calls.

  6. Mark the Topology Hiding checkbox if you want to enable Topology Hiding.

  7. In the Domain field, enter the realm created in the Bandwidth portal.

  8. In the SIP User ID field, enter the SIP username.

  9. In the Auth User field, enter the SIP username.

  10. In the Auth Password, enter the SIP password.

  11. For the following drop-down lists, select the corresponding default values:

  • Caller Name Policy

  • Caller Name on Forwarded Calls

  • Caller ID Policy

  • Caller ID on Forwarded Calls

  • P-Asserted-Identity(PAI)

  • PAI on Forwarded Calls

  1. Click the Add Trunk Profile button.

Result: The new Trunk Profile is created and displayed in a table on the SIP Trunk Profiles page.

Configuring the Trunk Settings for Users

Once the Trunk Profile is added, do the following to configure trunk settings for users:

  1. Log in to the ConnecttoTeams Enterprise Portal.

  2. From Trunks menu section, click on Users.

    The Manage Trunk Users page displays.


  3. Select the user to configure and click the Configure Trunk User link.


    The Configure Trunk Settings for User page displays.


  4. Specify the relevant trunk setting details for user. See the Configure Trunk Settings for Users documentation for information on trunk settings.

  5. Click Save Settings.

Note

Inform the Enterprise Global Admin to Sync Teams Users when the relevant user is created by users other than the Microsoft Global Admin.

Suggested Further Reading

See the Configure Trunk Settings for Users documentation for more information.

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