I have a situation where calls are failing to the SIP provider due to extra alert_info headers when using Follow Me. When an external party calls an extension’s DID where follow me is active, the call to the user’s mobile works fine. When an internal extension calls another extension with follow me active, FreePBX is placing extra ALERT_INFO headers in the INVITE and the carrier is rejecting the call (400 Bad Request) to the user’s mobile.
Below are captures of the PBX Invites to the carrier to dial the mobile follow me number. The first is acall originated from an external party, the second is what happens when its extension-to-extension.
INVITE that is sucessful (carrier completes the call)
Internet Protocol Version 4, Src: 10.31.254.1, Dst: 10.31.254.2
User Datagram Protocol, Src Port: 5060, Dst Port: 5060
Session Initiation Protocol (INVITE)
Request-Line: INVITE sip:[email protected] SIP/2.0
Message Header
Via: SIP/2.0/UDP 10.31.254.1:5060;branch=z9hG4bK4d9e83fa
Max-Forwards: 70
From: <sip:[email protected]>;tag=as67cb89dd
To: <sip:[email protected]>
Contact: <sip:[email protected]:5060>
Call-ID: [email protected]
CSeq: 102 INVITE
User-Agent: FPBX-13.0.194.10(13.15.0)
Date: Fri, 10 May 2019 22:07:46 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
Remote-Party-ID: "513xxxxxxx" <sip:[email protected]>;party=calling;privacy=off;screen=no
Content-Type: application/sdp
Content-Length: 326
Message Body
INVITE that fails, carrier rejects this invite with 400 Bad Request:
Internet Protocol Version 4, Src: 10.31.254.1, Dst: 10.31.254.2
User Datagram Protocol, Src Port: 5060, Dst Port: 5060
Session Initiation Protocol (INVITE)
Request-Line: INVITE sip:[email protected] SIP/2.0
Message Header
Via: SIP/2.0/UDP 10.31.254.1:5060;branch=z9hG4bK71df91b7
Max-Forwards: 70
From: <sip:[email protected]>;tag=as1e6ab0c0
To: <sip:[email protected]>
Contact: <sip:[email protected]:5060>
Call-ID: [email protected]
CSeq: 102 INVITE
User-Agent: FPBX-13.0.194.10(13.15.0)
Date: Fri, 10 May 2019 22:39:36 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
Alert-Info: ALERT_INFO:<answer>
Alert-Info: ALERT_INFO:<answer>
Alert-Info: ALERT_INFO:<answer>
Remote-Party-ID: "513xxxxxxx" <[email protected]>;party=calling;privacy=off;screen=no
Content-Type: application/sdp
Content-Length: 328