Source note · One SBC serving several calling platforms
If an INVITE or OPTIONS sent to the Teams SIP proxy carries an IP address rather than an FQDN as the Contact hostname, the connection is refused with 403 Forbidden.
Checked 2026-10-14
- Vendor
- Microsoft
- Product
- Teams Phone
- Subsystem
- Direct Routing
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-10-14
- Checked
- 2026-10-14
Sources
- Teams Phone System Direct Routing: SIP protocol — Microsoft · tier 2 current vendor documentation · Detailed requirements for Contact header and Request-URI > Contact header
Cite this note
APA
WarmTransfer. (2026, October 14). One SBC serving several calling platforms: source note multi-platform-sbc-design-teams-ip-in-contact-403. WarmTransfer. https://warmtransfer.net/knowledge/claims/multi-platform-sbc-design-teams-ip-in-contact-403
BibTeX
@misc{warmtransfer-claim-multi-platform-sbc-design-teams-ip-in-contact-403,
title = {One SBC serving several calling platforms: source note multi-platform-sbc-design-teams-ip-in-contact-403},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/multi-platform-sbc-design-teams-ip-in-contact-403},
note = {Source note multi-platform-sbc-design-teams-ip-in-contact-403, checked 2026-10-14}
}