Source note · DNS SRV and service discovery for SIP
Under RFC 3403 NAPTR records are processed in ascending ORDER value, with PREFERENCE choosing among records of equal ORDER, and a client must not simply use the first record with a known service.
Checked 2026-09-24
A client MUST process multiple NAPTR records in the order specified by the "order" field, it MUST NOT simply use the first record that provides a known Service Parameter combination.
- Vendor
- IETF
- Product
- DNS NAPTR
- Subsystem
- NAPTR
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 3403 (October 2002)
- Checked
- 2026-09-24
Sources
- RFC 3403: Dynamic Delegation Discovery System (DDDS) Part Three: The Domain Name System (DNS) Database — RFC Editor / IETF · tier 1 standards and regulators · NAPTR RR Format (ORDER and PREFERENCE fields) and the processing rules that follow
Cite this note
APA
WarmTransfer. (2026, September 24). DNS SRV and service discovery for SIP: source note dns-srv-voice-rfc3403-naptr-order. WarmTransfer. https://warmtransfer.net/knowledge/claims/dns-srv-voice-rfc3403-naptr-order
BibTeX
@misc{warmtransfer-claim-dns-srv-voice-rfc3403-naptr-order,
title = {DNS SRV and service discovery for SIP: source note dns-srv-voice-rfc3403-naptr-order},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/dns-srv-voice-rfc3403-naptr-order},
note = {Source note dns-srv-voice-rfc3403-naptr-order, checked 2026-09-24}
}