Source note · SIP registration failures
In the RFC 3665 successful registration example the first REGISTER is answered with 401 Unauthorized carrying a challenge, the UA resends REGISTER with credentials computed from that challenge, and the server then returns 200 OK.
Checked 2026-09-25
- Vendor
- not restricted
- Product
- SIP
- Subsystem
- registration
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 3665
- Checked
- 2026-09-25
Sources
- RFC 3665: Session Initiation Protocol (SIP) Basic Call Flow Examples — RFC Editor / IETF · tier 1 standards and regulators · Section 2.1 Successful New Registration, messages F1-F4
Cite this note
APA
WarmTransfer. (2026, September 25). SIP registration failures: source note sip-registration-failures-401-challenge-flow. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-registration-failures-401-challenge-flow
BibTeX
@misc{warmtransfer-claim-sip-registration-failures-401-challenge-flow,
title = {SIP registration failures: source note sip-registration-failures-401-challenge-flow},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-registration-failures-401-challenge-flow},
note = {Source note sip-registration-failures-401-challenge-flow, checked 2026-09-25}
}