SIP 301 Moved Permanently vs 423 Interval Too Brief
SIP 301 (Moved Permanently) is a 3xx Redirection response, while 423 (Interval Too Brief) is a 4xx Client Failure response. 301 indicates that the user can no longer be found at the address in the Request-URI. The client should direct future requests to the new address in the Contact header. In contrast, 423 means that the expiration time in the request is too short. The response contains a Min-Expires header indicating the minimum allowed value.
Description
The user can no longer be found at the address in the Request-URI. The client should direct future requests to the new address in the Contact header.
When You See It
When a user has permanently changed their SIP address. All future calls should be directed to the new URI.
How to Fix
Update your address book or routing tables to use the new Contact URI provided in the response.
Description
The expiration time in the request is too short. The response contains a Min-Expires header indicating the minimum allowed value.
When You See It
When a REGISTER or SUBSCRIBE request has an Expires value that is below the server's minimum. Common with aggressive keep-alive timers.
How to Fix
Increase the Expires header value to at least the Min-Expires value from the response.
Key Differences
301 is a 3xx Redirection response, while 423 is a 4xx Client Failure response.
SIP 301: The user can no longer be found at the address in the Request-URI. The client should direct future requests to the new address in the Contact header.
SIP 423: The expiration time in the request is too short. The response contains a Min-Expires header indicating the minimum allowed value.
You encounter 301 when when a user has permanently changed their SIP address. All future calls should be directed to the new URI.
You encounter 423 when when a REGISTER or SUBSCRIBE request has an Expires value that is below the server's minimum. Common with aggressive keep-alive timers.
When to Use Which
For 301 (Moved Permanently): Update your address book or routing tables to use the new Contact URI provided in the response. For 423 (Interval Too Brief): Increase the Expires header value to at least the Min-Expires value from the response.