We have been Cyber Essentials tested, whilst we passed, the have recommended that we look into:-
"Linux kernel TCP sequence number generation security weakness"
This is on our Mitel 5000 IP address, we have VOIP with the following ports open
3998-4000 TCP
443 TCP
4000 TCP
4444 TCP
20001 UDP
50098-50508 UDP
44000 TCP
69 UDP
6004-6261 UDP
6800-6802 TCP
22 TCP
Have we got any not required, could this cause this, or this this just one of those things.