AudioCodes MP-20x User Manual page 205

MP-20x Telephone Adapter
FTP port request to 3rd party is forbidden (Possible bounce attack) - a packet has
been blocked because of an unauthorized FTP port request.
Firewall Rules were changed - the firewall rule set has been modified.
User authentication - a message during login time, including both successful and
failed authentication.
First packet is Invalid - First packet in connection failed to pass firewall or NAT
Version 3.0.1 205
13. Security
July 2010