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Port 8433 (aws-as2)

IANA assigns port 8433 to aws-as2: Non Persistent Desktop and Application Streaming.

Registered (user) port, 1024-49151 UDP

Port 8433 is normally used over UDP; the checker tests TCP only, so a "filtered" result does not mean the UDP service is down.

IANA assignment

Service nameProtoDescriptionAssigneeReference
aws-as2 UDP Non Persistent Desktop and Application Streaming Amazon.com Services LLC -

Registry dates for this port: registered 2022-11-07.

Check what is listening on port 8433

Linux: UDP 8433
sudo ss -ulnp 'sport = :8433'
Linux / macOS: which process owns the port
sudo lsof -nP -i :8433
Windows (Command Prompt)
netstat -ano | findstr :8433
Windows (PowerShell)
Get-NetUDPEndpoint -LocalPort 8433

Test it from outside

UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 8433

Block port 8433 in the firewall

ufw
sudo ufw deny 8433/udp
iptables
sudo iptables -A INPUT -p udp --dport 8433 -j DROP
nftables
sudo nft add rule inet filter input udp dport 8433 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 8433' -Direction Inbound -Protocol UDP -LocalPort 8433 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.