Locating a server with RFC 3263

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An explicit transport or port skips the records that are no longer needed. A numeric IP skips the name.

Worked example

What happened before the INVITE The first note states the DNS result. The SIP itself contains no NAPTR records.

1. Read the first hop note.
2. Inspect the INVITE Request-URI.
3. Name the record that would have supplied a port.

Fault

The peer moved in DNS. The SBC still sends to 192.0.2.40 because the dial-peer target is a literal address. Calls time out.

RFC 3263 runs on a domain. An address skips it.

Quiz

Ecosystem

Glossary, sister systems, and the integration seam for this room.

Quality management and recording QM scores interactions. The standardized way an SBC forks a session to a recorder is SIPREC.

Glossary · Ecosystem map · Ports · Troubleshooting