In SIP digest authentication a user agent server challenges with 401 Unauthorized, while a proxy challenges with 407 Proxy Authentication Required.

Checked 2026-09-25

Vendor
IETF
Product
SIP
Subsystem
authentication
Deployment
any
Region
not restricted
Release range
RFC 3261
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP trunk carrier turn-up and acceptance testing: source note sip-trunk-carrier-turn-up-rfc3261-401-407. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trunk-carrier-turn-up-rfc3261-401-407

BibTeX

@misc{warmtransfer-claim-sip-trunk-carrier-turn-up-rfc3261-401-407,
  title  = {SIP trunk carrier turn-up and acceptance testing: source note sip-trunk-carrier-turn-up-rfc3261-401-407},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-trunk-carrier-turn-up-rfc3261-401-407},
  note   = {Source note sip-trunk-carrier-turn-up-rfc3261-401-407, checked 2026-09-25}
}

Read in context