If you are running your database or other critical systems on servers with OS X Server, it may be advisable to turn on the adaptive firewall.
The adaptive firewall helps prevent entry to your computer by unauthorized users over your network connections. OS X Server uses an adaptive firewall that dynamically generates a firewall rule if a user or an IP address generates 10 consecutive failed login attempts. The adaptive firewall is managed by the afctl command line utility. Certain IP addresses can be whitelisted with the afctl -w command, and you can add to the blacklist with the afctl -a command. Check the man pages for all options.
For how to enable the adaptive firewall and set it active also on system reboots, check this Knowledge Base article for the details. The KB shows you how to do it for OS X Server 10.7 through 10.10.