RFC 3581 tells clients to retransmit an INVITE about every 20 seconds, even after a provisional response, to keep the UDP NAT binding fresh. This shows the authors expected UDP NAT bindings to be short-lived.

Checked 2026-09-25

Vendor
not restricted
Product
SIP
Subsystem
nat-traversal
Deployment
any
Region
not restricted
Release range
RFC 3581
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP registration failures: source note sip-registration-failures-nat-binding-20s. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-registration-failures-nat-binding-20s

BibTeX

@misc{warmtransfer-claim-sip-registration-failures-nat-binding-20s,
  title  = {SIP registration failures: source note sip-registration-failures-nat-binding-20s},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-registration-failures-nat-binding-20s},
  note   = {Source note sip-registration-failures-nat-binding-20s, checked 2026-09-25}
}

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