-noIPX

IPX is a seperate, and older protocol to TCP/IP. Hlds usually starts with IPX ports enabled. If you are not using the IPX protocol, chances are you don't need it.

-nomaster

This option disables communication with the master hlds servers. The master server tracks hlds servers so clients can find them in "Internet Games", you server can check for updates, and checks client's game key when they log onto a server. You can usually leave this option unchecked.

-restart

This tells hlds to attemp to restart if it crashes. This is only if the game itself crashes, not the operating system.

+sv_lan

This option starts the server in a special mode tuned for LAN play. It expects a LAN speed connection, so don't use this unless all clients are connecting over a 10Mbits/sec or faster LAN

extra parameters

The previously mentioned options are pretty commonly used. There are more obscure options that some users might require and need a place to enter them. This field requires that you type the option exactly as how it would appear in the command line. Multiple parameters can be passed in this text field.