SIP Response Code Decoder
Paste a code, a response line, or a whole trace snippet. You get the meaning, the RFC reference, the causes that actually produce it in production, and what to check on the session border controller.
All 75 codes in the IANA SIP response code registry are here, though in practice a handful account for most of what you will ever see.
Browse every SIP response code
| Code | Name | Meaning | Seen in support cases |
|---|
About the frequency column. These bands are based on our own support history: 2,682 real cases across production SBC deployments. They show how often a response code appears in escalated support cases, not how often it appears in live network traffic. A code may be very common on the wire but rarely show up in support because it usually does not cause a problem. Use this column to help prioritize what to check first, rather than as a measure of how often a code occurs on your network.
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