Source note · SIP call forwarding and routing loops
Under RFC 5393, a proxy that forks a request to more than one destination must ensure the request is not looping through it; Via-based loop detection is recommended, but other mechanisms are allowed.
Checked 2026-09-25
- Vendor
- IETF
- Product
- SIP
- Subsystem
- forking proxy loop detection
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 5393 onward
- Checked
- 2026-09-25
Sources
- RFC 5393: Addressing an Amplification Vulnerability in Session Initiation Protocol (SIP) Forking Proxies — IETF / RFC Editor · tier 1 standards and regulators · Section 4 (Normative changes to RFC 3261), loop-detection requirement
Cite this note
APA
WarmTransfer. (2026, September 25). SIP call forwarding and routing loops: source note sip-forwarding-loops-forking-must-detect. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-forwarding-loops-forking-must-detect
BibTeX
@misc{warmtransfer-claim-sip-forwarding-loops-forking-must-detect,
title = {SIP call forwarding and routing loops: source note sip-forwarding-loops-forking-must-detect},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-forwarding-loops-forking-must-detect},
note = {Source note sip-forwarding-loops-forking-must-detect, checked 2026-09-25}
}