the only way to get the SteamID list is to connect to the real source client and issue the console command "status".
There are cfg-based solutions that dynamically generate special cfg files (which will be loaded by the game) with commands for connecting to several servers in series and issuing the "status" command. SteamID will be written to the console log file (and can be easily analyzed).
These programs are called "server scanners" or "steam scanners" and are mainly used for fraudulent and statistical purposes and can be found in official forums (facepunch.com is currently missing) https://www.google.com/?q= site: facepunch.com% 20server% 7Csteamid% 20scanner
Sanya_zol
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