This is for older games like CS 1.6 (default game) and other servers that still run on the older HLDS server under id 90
ReHLDS is a reverse engineered build of the original HLDS (build 6152/6153), and provides a number of fixes and improvements over the vanilla engine files, while remaining compatible with vanilla clients.
Github: https://github.com/dreamstalker/rehlds
HLDS servers require up to 6 ports
| Port | default |
|---|---|
| Game/rcon | 27015 |
| HLTV | 27020 |
| VAC | 26900 |