The halflife-admin-0.84.zip file you have requested: Tools and Utilities / Misc / Half-Life Admin Mod v0.84 - 321.49kb is not available. Perhaps try browsing all files for the game Half-Life and upload any files you want to share or are missing. This is the only information we could locate:
This mod will let you give people access to your servers, without giving access to rcon. It also lets you define users who can access the server, each with a different password.