Securing your Network
The Need for Firewall Protection
A true firewall is the starting point to put your security policies in place. Many companies tout their hardware as being firewalls, but be careful! A true firewall offers stateful packet inspection and automatic blocking of known intrusion attemps. Hacking, whether it's into your company's network or your personal computer at home, can have serious consequences. For example:
- Lost Data - If someone were to delete data from your system(s), would you notice right away? How much would it cost you to recreate that data?
- Down Time - If someone is able to breach your security, they could take down your internet connection and cause financial impact due to loss of services.
- Computer Jacking - Hackers who get control of your computer can launch attacks against other networks using your computer. When the cyber police find out, guess who they're going to be looking for?
Attacks, like those previously mentioned, occur in many forms. Some are minor while others create havoc and do a lot of damage. Here are some others that you need to protect your network against:
- Denial of Service (DoS)
- Denial of Service attacks are designed to prevent users from accessing a service or resource like a company's public Web site on the Internet.
- Viruses - A virus is a computer program that attaches itself to another program and spreads from file to file when that program is run.
- Worms - Worms are similar to viruses, except that instead of spreading from file to file, they spread from computer to computer.
- Trojan Horses - Like the ancient Greek saga, a Trojan horse is a gift with a little something extra inside. Unfortunately this "gift" usually causes serious problems for your computer.
Firewall Functionality
Firewalls are a great way to protect your business or home network against attacks from intruders. They're designed to defend against attack by implementing a series of rules that permit, or deny, traffic to pass between your network and the Internet. Based on the way these rules are set, the inbound and outbound flow of information maybe extremely tight or very relaxed. The trick is to maintain a balance between your company's need for security and your employees' need to get their work done without interference.
So what else do firewalls do besides screening email and Web requests? In general, firewalls should have the following functions at a minimum:
- Stateful Packet Inspection - Stateful Packet Inspection is a smarter form of packet filtering, which inspects headers of network "packets." It blocks any packet arriving at the firewall claiming to be a solicited response.
- Network Address Translation (NAT)
- NAT is a technique that hides the IP addresses of your internal computers from prying eyes by replacing them with a single public IP address.
- Application Proxy - This service allows firewalls to inspect more than just packet headers before deciding whether or not to allow a packet to pass through.
- Monitoring and Logging - Keeping records of attacks is important. It will help you analyze your security needs and provide you with feedback on the performance of your firewall.
As good as firewalls are at defending your network against unwanted intrusions, they can't protect against everything. What threats can't they protect against? Here are a few:
- Malicious Authorized Users - These are people on the internal network who are already behind the firewall, which makes this threat difficult to defend against.
- Social Engineering - Sometimes hackers obtain information by calling employees and posing as a co-worker or someone else in the company doing a routine check.
- Viruses, Worms and Trojan Horse Programs - Firewalls scan network traffic for these threats, however the programs are changing constantly, making them hard to detect.
- Poor Network Administration - A firewall is only as effective as its programming. It's up to the network administrator to determine which network traffic should be allowed to pass and which shouldn't.
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Over the years, we have found there is great benefit in periodically "rebuilding" your systems. This provides many functions, including: clearing out corrupt preferences and applications, basic organization, repairing a bad or slugging operating system and clearing old data off. When we do a full rebuild for a client, the process is very straight forward: Back-up the hard drive, reformat the hard drive, clean load of Mac OS 9 (if needed) with all patches, clean load of Mac OS X (current version) with all patches, clean load of ALL applications with patches, restore only pertinent user data and full maintenane on the system.
