SIP 199 Early Dialog Terminated vs 403 Forbidden
SIP 199 (Early Dialog Terminated) is a 1xx Provisional response, while 403 (Forbidden) is a 4xx Client Failure response. 199 indicates that a UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs. In contrast, 403 means that the server understood the request but is refusing to fulfill it. Authorization will not help. The request should not be repeated.
Description
A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
When You See It
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
How to Fix
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.
Description
The server understood the request but is refusing to fulfill it. Authorization will not help. The request should not be repeated.
When You See It
When the server policy denies the request regardless of credentials. Common for blocked numbers, restricted routes, or ACL violations.
How to Fix
Check server ACLs and routing policies. Verify the caller is permitted to make this type of call. Contact the server administrator if the block is unexpected.
Key Differences
199 is a 1xx Provisional response, while 403 is a 4xx Client Failure response.
SIP 199: A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
SIP 403: The server understood the request but is refusing to fulfill it. Authorization will not help. The request should not be repeated.
You encounter 199 when in forked call scenarios when one of the forked branches is cancelled because another branch was answered.
You encounter 403 when when the server policy denies the request regardless of credentials. Common for blocked numbers, restricted routes, or ACL violations.
When to Use Which
For 199 (Early Dialog Terminated): No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully. For 403 (Forbidden): Check server ACLs and routing policies. Verify the caller is permitted to make this type of call. Contact the server administrator if the block is unexpected.