Some internet service providers, notably Verizon, block SIP traffic on the default port 5060. Because of this, users of those providers are not able to register/use softphones while on those providers’ mobile data networks. To solve this issue we need to enable an alternate port within the SBCs with which those users can access their PBX. Note that the alternate port needs to be added in each SBC HA pair where that phone might attempt a registration. At present this means adding the port in both Atlanta and Dallas.
There are three primary steps necessary to enabling an alternate port on an SBC:
- Adding an Access Service Port for the UDP port on which you’d like to allow traffic
- Adding a SIP Access Resource for the PBX
- Edit the FQDN Route for the PBX
An Access Service Port for UDP port 5070 has already been added to the SBC configuration with an alias of
External - Access2 and an index of
5. Unless you have a very specific need to use another port, please use this one when specifying a non-default port. This guide does not cover the specifics of adding an additional Access Service Port as doing so should not be necessary except in rare circumstances.
Adding a SIP Access Resource
To add a SIP Access Resource, you need to be logged into the SBC using an account with write access. Once logged in, go to the System tab, select the Advanced sub-tab, and click the button labeled Save Config in order to make a backup of the SBC configuration (necessary if there are any issues with adding the new resource).
Once done, go to the Resources tab and search for the customer for whom you will be adding the new resource. By default each customer should have three resources:
- a SIP Peering Resource for the SBC on service port
- a SIP Peering Resource for the PSTN on service port
- and a SIP Access Resource for the FQDN on service port
Locate the SIP Access Resource on port
2 and click on the  link on the right side of the page. Carefully make a note of all of the settings (write them down, take a screenshot, copy/paste, etc) as the new resource we’ll be adding will be using the same settings with the exception of two changes. Once you have the settings recorded, click the Cancel button to return to the previous screen.
At this point you will need a Trunk ID for the new resource. Within Papal, access the PBX settings and click to edit the Misc. Data panel. The placeholder in the Port 5070 Trunk field will indicate the next available ID. Please enter the ID number into the field, save the changes, and use that ID for the Trunk ID when adding the resource in each applicable SBC. If you do not have access to the PBX settings, please request the trunk ID from a CST, a developer, or a sysadmin.
Click on the Add button toward the upper left corner of the screen to add a new resource and enter the recorded settings exactly as they were entered in the resource you are copying with three exceptions:
- In the field labeled Trunk ID, enter the ID from above.
- In the field labeled Name append some indication that this is an alternate port resource.
- In the dropdown labeled Service Port, select
External - Access2:5
Once done, double and triple check all your settings to ensure the remainder match the original resource. When you are confident that all the settings are correct, click the Add button toward the upper left corner of the screen.
Edit the FQDN Route
At this point we need to edit the FQDN Route for the PBX so that everything routes as it should. To do this, click on the Routes tab and select the FQDN Route for the PBX in question. Click the
 button for the route and locate the table toward the bottom of the page. Click on the next available Trunk ID dropdown and select the newly added SIP Access Resource you added above. When done, click the
Submit button to save your changes.
At this point the new SIP Access Resource should be active. Please take a moment to ensure you can register devices on both ports 5060 and 5070. You can use mobile device softphones such as Bria and Zoiper for this. During the device setup, replace the outbound proxy address with the following:
If you are not able to register devices using both ports, there is an error somewhere that requires addressing. Please consult with a CST, developer, or sysadmin to troubleshoot the issue.