Instructions
On your PC, locate the "server.cfg" file found in "C:\Program Files\Valve\CStrike."
Right-click on the server.cfg file and select "Open with..." from the drop-down menu.
Navigate using the scroll bar until you find Notepad. Highlight it and click "OK" at the bottom.
Go to the last line of text after the Notepad window reading "server" opens and hit enter twice on your keyboard to create a new blank line.
Type in "sv_airaccelerate 300" (without quotes) and hit "Enter" on your keyboard twice.
Type in "sv airmove 10" (without quotes).
Select File and Save in Notepad, then exit the program.
Start Counter-Strike 1.6 as you normally would. Now when you host a network game, the settings allow players to "surf" on the landscape.