SIP 200 OK
What SIP 200 means
Not an error. It is the success response, whether that is a call being answered or a registration being accepted. If you are reading a log to diagnose a fault, a 200 marks the parts that worked.
What SIP 200 OK actually means
The request succeeded, and the information returned depends on what was asked. It confirms an answered call, an accepted registration or a completed in-call change, so it is the marker for everything that went right.
What causes SIP 200 on a business phone system
- A call was answeredThe normal response to an answered call.
- A registration was acceptedA phone that registers successfully gets one, which is the response to look for when diagnosing registration problems.
- An in-call change completedHold, resume and transfer each renegotiate the call and each is confirmed this way.
How to fix SIP 200
- Use it to bracket the failure in a traceFind the last 200 before things go wrong. Everything up to that point worked, which narrows the investigation considerably.
- A registration 200 followed by call failures points at outbound authenticationThat pattern means identity is fine and the problem is permission or call-level credentials, so read up on 403 and 407 rather than re-entering passwords.
Fixing the underlying problem
This page explains the code. These guides walk through the fix in detail.
Questions about SIP 200
What does SIP 200 OK mean?
The request succeeded. Depending on what was asked, it means a call was answered, a phone registered, or an in-call change such as hold or transfer completed. When reading a trace it is the marker for what worked.
Related SIP response codes
Source. SIP 200 OK is defined in RFC 3261 section 21.2.1 and registered in the IANA SIP Parameters — Response Codes. The causes and fixes above are drawn from our own experience supporting UK business phone systems.