From their Website
Team Fortress 2 is a team-based multiplayer first-person shooter developed by Valve. Players choose from nine character classes across game modes like Capture the Flag, Control Point, Payload, and King of the Hill.
| RAM | CPU | Storage |
|---|---|---|
| 2-4 GB | 2 Cores | 20 GB |
TF2 needs 3 ports: a Primary Allocation for the game/RCON port, plus 2 Additional Allocations for the Client and SourceTV ports (set those two variables to match).
| Port | Default | Allocation |
|---|---|---|
| Game/RCON | 27015 | Primary |
| Client | 27005 | Additional |
| SourceTV | 27020 | Additional |
Public servers need a free Game Server Login Token from https://steamcommunity.com/dev/managegameservers (pick "Team Fortress 2"), set as the GSLT variable. Without one the server still runs, it just won't show up in the server browser.