RFC 5626 lets a proxy reuse the flow a user agent opened when registering to deliver later inbound requests, so the UA can receive calls through NATs and firewalls that block inbound connections.
Checked 2026-10-02
- Vendor
- not restricted
- Product
- not restricted
- Subsystem
- NAT traversal
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 5626
- Checked
- 2026-10-02
Sources
- RFC 5626: Managing Client-Initiated Connections in the Session Initiation Protocol (SIP) — IETF / RFC Editor · tier 1 standards and regulators · Section 3.1
Cite this note
APA
WarmTransfer. (2026, October 2). SIP trunk authentication: registration and static IP and mutual TLS: source note sip-trunk-authentication-models-rfc5626-outbound-flow-reuse. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trunk-authentication-models-rfc5626-outbound-flow-reuse
BibTeX
@misc{warmtransfer-claim-sip-trunk-authentication-models-rfc5626-outbound-flow-reuse,
title = {SIP trunk authentication: registration and static IP and mutual TLS: source note sip-trunk-authentication-models-rfc5626-outbound-flow-reuse},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-trunk-authentication-models-rfc5626-outbound-flow-reuse},
note = {Source note sip-trunk-authentication-models-rfc5626-outbound-flow-reuse, checked 2026-10-02}
}