I was just informed that I need to install a firewall by the end of next week! I am rather clueless on this subject and I could use some suggestions. This would reside on a multihomed NT machine for a single domain of about 100 users, using TCP/IP. It will have to be place between the network and an outsourced Cisco router. We are using DHCP and RAS, but we aren't using WINS or hosting a web site. Any suggestions on software, hardware, or setup would be greatly appreciated. Sorry, I know it's alot to ask in one question. Thanks!

You can establish a firewall many different ways. In your scenario I would use your cisco router as a firewall. You can configure the router to be a firewall. I don't know what series of router you have, but all routers can be used as firewalls. You may need to purchase a special card from Cisco if your router is not firewall enabled.

You can also use another computer as a firewall. Install Windows NT of the computer and make configure it to use its own subnet and IP address. Install Proxy Server on the computer and configure Proxy as your firewall.

Another easy way is to download the software zonealarm at www.zonealarm.com and configure it to be a firewall.

Download from http://www.zonelabs.com/ their free firewall for personel use.
First go to www.grc.com and run the port sniffer to establish your basline. You should see a great deal of your ports OPEN. Then run Zonelabs firewall setup with their online manual help and then run the sniffer again.
You should see a big difference in ports close/open versus ports stealthed. I was hacked 3x in two weeks, nobody got in. Zonelabs is highly recommended by many mags.
It works in here.
Good luck.

Let me tell you something about a firewall

A firewall is a set of related programs, located at a network gateway server, that protects the resources of a private network from users from other networks. (The term also implies the security policy that is used with the programs.) An enterprise with an intranet that allows its workers access to the wider Internet installs a firewall to prevent outsiders from accessing its own private data resources and for controlling what outside resources its own users have access to.

For more information on firewall, please visit the links given below:
http://www.whatis.com/firewall.htm
http://csrc.ncsl.nist.gov/nistpubs/800-10/node30.html

I too am researching firewalls. Here is one website I've found that has given me lots of information:

http://www.icsa.net/

Good luck.
--Kevin

you can go with a physical firewall
Sonic wall SAHO 50 or the one more capable for vpn etc this is an inexpensive fire wall.
you might want to check.

I think the hot software based firewall solution right now is CheckPoint's product.

Runs on NT.

Most of the newer CISCO routers do have some sort of firewall built in. I don't think they give you as much control as the software or other hardware varieties.

zonelabs is good for personal use, but for the corporate envioronment, you need something better than a $20-200 product.

www.greatcircle.com has some good firewall info as well as a discussion group.

good luck,