Source note · SIP call forwarding and routing loops
RFC 7332 requires B2BUAs to check the received Max-Forwards value and to reject or respond to the request, rather than pass it on, when the value is zero.
Checked 2026-09-25
- Vendor
- IETF
- Product
- SIP
- Subsystem
- B2BUA loop detection
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 7332 (August 2014) onward
- Checked
- 2026-09-25
Sources
- RFC 7332: Loop Detection Mechanisms for Session Initiation Protocol (SIP) Back-to-Back User Agents (B2BUAs) — IETF / RFC Editor · tier 1 standards and regulators · Section 3 B2BUA Behavior
Cite this note
APA
WarmTransfer. (2026, September 25). SIP call forwarding and routing loops: source note sip-forwarding-loops-b2bua-check-zero. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-forwarding-loops-b2bua-check-zero
BibTeX
@misc{warmtransfer-claim-sip-forwarding-loops-b2bua-check-zero,
title = {SIP call forwarding and routing loops: source note sip-forwarding-loops-b2bua-check-zero},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-forwarding-loops-b2bua-check-zero},
note = {Source note sip-forwarding-loops-b2bua-check-zero, checked 2026-09-25}
}