Firewall / Proxy Software recommendation for a large network

We are currenlty using ISA 2006, out of date and causing a lot of issues. I wish to install a new firewall software based solution and was wondering what you would recommend.

I want the solution to do the following:
1) Act as a proxy server
2) Allow authenicated users in externally
3)Possible DHCP & DNS roles

Any feedback is appreciated
James DanahayDirectorAsked:
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Mad-MacConnect With a Mentor Commented:
I propose a solution:

Download link:

Very simple free solution. Knowledge of Unix - not required :)
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