why should I use a firewall with dsl

[glenrose]

hi:

connecting to the net opens a port to allow you out, does outlook for email open a seperate port, and how many additional ports open as well, is there a great need for a software firewall, or is it just letting you know when you try to send info out to the net.

thanks

[gonzo4904]

Firewalls are a Good thing.

Now you are correct about the ports, but there can be a lot more than you thing. not sure exactly how many but a bunch. Take an example of UDP ports. I believe there are well over 17,000. Not to mention TCP ports, most likely a lot more.

Now firewalls come in 2 BASIC( i know there a different varations so dont spam me)types.

You have your Hardware and your Software.

Hardware Firewalls(SOHO) are usually found in routers. At least for the average consumer PC user. It uses a method called NAT(Network Address Translation) to help protect a users PC. Now NAT will serve 2 purposes, one will provide you computer with an internal IP address(ex: 192.168.1.100). Two is that will will block any unsolicited(and sometimes solicited) traffic from going to your computer. Any network scans, port probes, etc. will be blocked by the router. Pros: effective and seemless, Cons: Routers are not that cheap. especially if you get a fully optioned one.

Software firewalls are perhaps the easiest and least(meaning sometimes free) expensive. They work be a means called Application control. Which basically works like a bouncer at a nite club. Lets say you have an "ID". Now the Bouncer"firewall" looks at your ID and lets you in. Now if you have an ID, but your not on the list it will block you. The same for data packets on the internet. If your on the list and it recognizes you"program" you go, if not you get blocked. Go here to learn more and get a free firewall which is probably the best and most recommend firewall. www.zonealarm.com

Firewalls keep bad stuff out, and also bad stuff from leaving. Also a way to make you pc invisible to outside intruders. go to www.grc.com and probe your ports(Shields Up) and see if you are vunerable. if you are it will give you some suggestions to help harden your defenses.

hope that helps.