Command name to execute or response code to return
$action = an internal command name $action = a SIP response code
If an internal command name is specified, the server executes the command.
If a SIP response code is specified, the server returns the response packet with the specified response code to the matched request and the session will not be routed.
$action = 200
Returns the response “200 OK”.
$action = block
Blocks matched incoming SIP requests and adds their source IP addresses in the Blocked IP Address database.