A few simple things are essential for the security of any network connected to today's hostile Internet.
All software, operating systems and applications, needs regular updates
to remove vulnerabilities as they are discovered.
These patches should be installed as promptly as possible
after they have been properly tested.
Particular care needs to be paid to applications for which
automatic updating is not practicable;
for example, most
Everyone should use
A firewall partitions one network from another, enforcing a policy on precisely what traffic is allowed to pass between the two networks. More sophisticated (and expensive) firewalls are able to enforce more sophisticated policies and handle higher levels of traffic. Although all do some good, there are many options to be researched when choosing a firewall.
Not only does a backup of your data protect you from hardware failure but it also protects you from human error and data corruption. Backups should be made often and regularly and tests scheduled so that data can easily be recovered when a real problem occurs.
Log records of activity on your systems are essential tools
for the investigation of an incident after it has occurred.
You should configure appropriate, manageable levels of logging
and ensure that you have procedures for storing and accessing them
while they are current and destroying them after that.
Regular examination of logs (which can be partly automated) will often draw attention to issues before they become a serious incident.
There is a separate page of advice on log files: