RFC 4320 forbids a transaction-stateful SIP element from sending a 408 response to a non-INVITE request.

Checked 2026-09-25

A transaction-stateful SIP element MUST NOT send a response with Status-Code of 408 to a non-INVITE request.
Vendor
not restricted
Product
SIP
Subsystem
transactions
Deployment
any
Region
not restricted
Release range
RFC 4320 (updates RFC 3261)
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP registration failures: source note sip-registration-failures-no-408-non-invite. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-registration-failures-no-408-non-invite

BibTeX

@misc{warmtransfer-claim-sip-registration-failures-no-408-non-invite,
  title  = {SIP registration failures: source note sip-registration-failures-no-408-non-invite},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-registration-failures-no-408-non-invite},
  note   = {Source note sip-registration-failures-no-408-non-invite, checked 2026-09-25}
}

Read in context