Yes.. you can run a server kit from any computer that is running a P IV or higher with at least 512 Mb system ram and XP (you can run from Vista with 1.5 GB RAM as well)
Now limitations are :
1. Bandwidth.. You need a cable connection that has at least 786 Kbps downstream and 512 kbps upstream.. this will be stable for 18 players plus yourself. you can get better cable connections from your providers.. My connection is running 30 Mbps down and 2 Mbps up for $39.99 a month .. Time Warner Road Runner Turbo with Speed Boost.
2. CPU... in order to host the server and play off the same machine, you need at least a Core 2 processor of 2.2 Ghz @ 800 Mhz FSB for smooth operation with several players online.
3. Server side text chat. Since your IP will be the basis for the server side text chat (with D.Net being the host).. trying to log in as a player will cause you to not be able to have in game text chatting on the server itself.. text chat is fine in missions though, but not on the server side chat room. All controls will not work.. you can see what you type, but the chat room will be like it is firewalled so commands won't process nor will text transmit.. this is because your Server Kit is using your IP address to host the IRC chat.. and IP addresses can not duplicate on IRC.. as such your game client will be blocked if the server is running on the same IP address / machine.