SIP 200 OK vs 482 Loop Detected
SIP 200 (OK) is a 2xx Success response, while 482 (Loop Detected) is a 4xx Client Failure response. 200 indicates that the request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully. In contrast, 482 means that the server has detected a loop. The request was received with its own address in the Via header, indicating it has been forwarded back to itself.
Description
The request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully.
When You See It
When a call is answered (INVITE 200 OK), a registration succeeds (REGISTER 200 OK), or a subscription is accepted (SUBSCRIBE 200 OK).
How to Fix
No fix needed — this is a success response. The caller should send an ACK to complete the three-way handshake for INVITE transactions.
Description
The server has detected a loop. The request was received with its own address in the Via header, indicating it has been forwarded back to itself.
When You See It
When routing configuration causes a request to cycle between two or more proxies without reaching the callee.
How to Fix
Review proxy routing tables and DNS records. Check for circular references in SIP routing. Fix the routing configuration to break the loop.
Key Differences
200 is a 2xx Success response, while 482 is a 4xx Client Failure response.
SIP 200: The request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully.
SIP 482: The server has detected a loop. The request was received with its own address in the Via header, indicating it has been forwarded back to itself.
You encounter 200 when when a call is answered (INVITE 200 OK), a registration succeeds (REGISTER 200 OK), or a subscription is accepted (SUBSCRIBE 200 OK).
You encounter 482 when when routing configuration causes a request to cycle between two or more proxies without reaching the callee.
When to Use Which
For 200 (OK): No fix needed — this is a success response. The caller should send an ACK to complete the three-way handshake for INVITE transactions. For 482 (Loop Detected): Review proxy routing tables and DNS records. Check for circular references in SIP routing. Fix the routing configuration to break the loop.