In SIP digest authentication a user agent server challenges with 401 and a WWW-Authenticate header, while a proxy challenges with 407 and a Proxy-Authenticate header.

Checked 2026-09-25

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

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP scanning and telephony denial of service: source note sip-scanning-tdos-rfc3261-digest-challenges. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-scanning-tdos-rfc3261-digest-challenges

BibTeX

@misc{warmtransfer-claim-sip-scanning-tdos-rfc3261-digest-challenges,
  title  = {SIP scanning and telephony denial of service: source note sip-scanning-tdos-rfc3261-digest-challenges},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-scanning-tdos-rfc3261-digest-challenges},
  note   = {Source note sip-scanning-tdos-rfc3261-digest-challenges, checked 2026-09-25}
}

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