Microsoft forwards History-Info entries marked private as-is to the SIP trunk provider because it treats that provider as a trusted peer.
Checked 2026-10-02
- Vendor
- Microsoft
- Product
- Teams Phone Direct Routing
- Subsystem
- SIP proxy
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Checked
- 2026-10-02
Sources
- Teams Phone System Direct Routing: SIP protocol — Microsoft · tier 2 current vendor documentation · History-Info header (Note)
Cite this note
APA
WarmTransfer. (2026, October 2). SIP identity headers: P-Asserted-Identity and Diversion and History-Info: source note sip-identity-headers-teams-hi-private-passed. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-identity-headers-teams-hi-private-passed
BibTeX
@misc{warmtransfer-claim-sip-identity-headers-teams-hi-private-passed,
title = {SIP identity headers: P-Asserted-Identity and Diversion and History-Info: source note sip-identity-headers-teams-hi-private-passed},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-identity-headers-teams-hi-private-passed},
note = {Source note sip-identity-headers-teams-hi-private-passed, checked 2026-10-02}
}