Over the next several weeks, LoopUp will be rolling out changes across its network to enforce the presence of the P-Asserted-Identity (PAI) header in all SIP INVITE messages originating from SIP trunking customers.
What's changing: In accordance with RFC 3325, LoopUp's network will begin strictly validating that all INVITE requests include a valid P-Asserted-Identity header. INVITEs that do not include this header will be rejected with:
SIP/2.0 403 Forbidden Reason: P-Asserted-Identity header not present
Why this is happening: This change is required for security and regulatory compliance. PAI is used to assert the verified identity of the calling party within a trusted network boundary. Enforcing its inclusion ensures that all calls traversing LoopUp's network carry authenticated originating identity, supporting fraud prevention and telco regulations.
Action required: As per previous communication, if you operate a SIP trunk connected to LoopUp, please ensure your equipment is configured to include a P-Asserted-Identity header in all outbound INVITE requests. Please refer to your SBC or PBX vendor documentation for configuration guidance.
If you have questions or need assistance validating your configuration ahead of the change, please contact servicedesk@loopup.com
Posted Jul 23, 2026 - 07:45 UTC
This scheduled maintenance affects: Cloud Telephony (North America, Latin America, Europe, the Middle East and Africa, South Africa, Asia-Pacific, Oceania).