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Port 333 (texar)

IANA assigns port 333 to texar: Texar Security Port.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
texar TCP Texar Security Port Eugen Bacic -
texar UDP Texar Security Port Eugen Bacic -

Check what is listening on port 333

Linux: is anything listening on TCP 333?
sudo ss -tlnp 'sport = :333'
Linux: UDP 333
sudo ss -ulnp 'sport = :333'
Linux / macOS: which process owns the port
sudo lsof -nP -i :333
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':333 '
Windows (Command Prompt)
netstat -ano | findstr :333
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 333 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 333
From Windows
Test-NetConnection HOST -Port 333
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 333

Block port 333 in the firewall

ufw
sudo ufw deny 333/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 333 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 333 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 333' -Direction Inbound -Protocol TCP -LocalPort 333 -Action Block
ufw
sudo ufw deny 333/udp
iptables
sudo iptables -A INPUT -p udp --dport 333 -j DROP
nftables
sudo nft add rule inet filter input udp dport 333 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 333' -Direction Inbound -Protocol UDP -LocalPort 333 -Action Block

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All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.