RFC 3263 specifies that if no NAPTR records are found, a SIP client constructs SRV queries for the transports it supports.

Checked 2026-09-25

If no NAPTR records are found, the client constructs SRV queries for those transport protocols it supports, and does a query for each.
Vendor
IETF
Product
SIP
Subsystem
server location
Deployment
on-premises, multi-tenant
Region
not restricted
Release range
RFC 3263
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). Expressway business-to-business calling: source note expressway-b2b-calling-rfc3263-srv-without-naptr. WarmTransfer. https://warmtransfer.net/knowledge/claims/expressway-b2b-calling-rfc3263-srv-without-naptr

BibTeX

@misc{warmtransfer-claim-expressway-b2b-calling-rfc3263-srv-without-naptr,
  title  = {Expressway business-to-business calling: source note expressway-b2b-calling-rfc3263-srv-without-naptr},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/expressway-b2b-calling-rfc3263-srv-without-naptr},
  note   = {Source note expressway-b2b-calling-rfc3263-srv-without-naptr, checked 2026-09-25}
}

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