We have a number of 2820 and use port redirection to open standard SBS ports. However, the server event logs indicate that there are random hacking attemps over various ports. The attempts are approximately every 1 minute, and are from multiple source IP addresses.
Given that the hack attempts are reaching the server, this would indicate that ports are open on the router. Typically, I would expect all ports to be locked down unless opened for a specific purpose.
Can anyone please advise on how to lock down all ports, and to only allow access to those that are required through port redirection.