Hi everyone, I’m having a strange network issue on my Singtel home connection.
Web browsing works fine (Google Chrome, YouTube, etc.), but all online games cannot connect, including:
• CS2 (Counter-Strike 2)
• Steam client
• Riot games (Valorant / LOL)

Here are the symptoms:
1. Steam and CS2 get stuck at “Connecting to CS2 network…”
2. Riot client cannot connect to the servers
3. DNS lookup for Valve servers fails:

Name resolution of cm1-sgp1.valve.net failed


4. UDP ports used by Steam / CS2 do not respond:

Test-NetConnection -Port 27015 → PingSucceeded = False


5. Even Cloudflare WARP / VPN does not fix the issue
6. Chrome browsing works perfectly, only games are affected

I tried:
• Changing DNS (1.1.1.1 / 8.8.8.8)
• Resetting network settings
• Flushing DNS
• Reinstalling Steam
• Using VPN
• PC works fine on other networks

So it looks like Singtel is blocking or failing to route UDP game traffic / Valve domains, or my ONR is malfunctioning.

Has anyone encountered this on Singtel recently?
Any fix (DMZ, UPnP, NAT Full Cone, ONR reboot, or routing issue)?
Would appreciate any advice.

Thanks!