RFC 3263 defines the NAPTR service field values SIP+D2U for UDP, SIP+D2T for TCP, SIP+D2S for SCTP and SIPS+D2T for TLS over TCP.

Checked 2026-09-24

Vendor
IETF
Product
SIP
Subsystem
NAPTR
Deployment
any
Region
not restricted
Release range
RFC 3263 (June 2002)
Checked
2026-09-24

Sources

Cite this note

APA

WarmTransfer. (2026, September 24). DNS SRV and service discovery for SIP: source note dns-srv-voice-rfc3263-naptr-services. WarmTransfer. https://warmtransfer.net/knowledge/claims/dns-srv-voice-rfc3263-naptr-services

BibTeX

@misc{warmtransfer-claim-dns-srv-voice-rfc3263-naptr-services,
  title  = {DNS SRV and service discovery for SIP: source note dns-srv-voice-rfc3263-naptr-services},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/dns-srv-voice-rfc3263-naptr-services},
  note   = {Source note dns-srv-voice-rfc3263-naptr-services, checked 2026-09-24}
}

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