Firewall ? 4 Kaiser

Nssca · Jan 6, 2010

I know you cant use more than one anti-virus on a PC but is it OK to use more than one firewall?
I use Sygate pro 5.6
Thanks for your time.

Kaiser · Jan 6, 2010

DaRooster said:
I know you cant use more than one anti-virus on a PC but is it OK to use more than one firewall?
I use Sygate pro 5.6
Thanks for your time.

No, they will most certainly trip over themselves. The bad thing with more than one firewall is that it has the ability to expose you even more. Yes, you read that right. Because of the way packets are formed, and the way ports are used, you can actually cause an operating system to open the ports that you dont want to have open with more than one firewall. Let alone the obvious, that it will slow your network traffic down. Also, UDP does not like to go through multiple firewalls, or even a single firewall in some cases due to the fact that it has no handshake. All it does is send the packets that get assembled at either end of the transmission. It waits for no return reply, essentially. If the packets are too large, the packet itself can get snipped which causes the packet transfer itself to fail. Now with TCP, the sender says it is sending some packets to the reciever. It then replies each time it recieves a packet successfully, then sends the next bpackets until it can assemble the whole file. This is why TCP, while not as fast as UDP because of the extra traffic caused by the handshake and the confirmation of delivery, is more stable and wmore resilient to transfer failures. While this is not the whole technical picture it will give you an idea of how it works. For more info on TCP vs UDP you can read about the RFC here:

**broken link removed**

Incidentally, RFC is a term used in computer industry world wide. What it means is Request For Comment. The smart thing that computer software and driver engineers came up with is a humble way to propose a solution. They realized, much like our forefathers did when they wrote the Consitution, is that it should have the ability to be ammended whenever necessary. In other words, RFC is a way that if someone finds a hole or a bug in code or the way something is designed, all they do is bring the problem or propositon to the table, and consideration for the new or revamped design goes underway. Essentially, they realized that humans make mistakes and encourage free thought for improvement. This happened about 2 years ago with an old, old RFC: DNS. DNS was gound to have an exploitable hole, and RFC at that point changed to fix the code. Then Microsoft, Apple, Cisco, Linux, Unix and just about every other device that uses DNS for IP resolution came out with patches to remediate the hole.