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Port 1743 (cinegrfx-lm)

IANA assigns port 1743 to cinegrfx-lm: Cinema Graphics License Manager.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cinegrfx-lm TCP Cinema Graphics License Manager Rodney Iwashina -
cinegrfx-lm UDP Cinema Graphics License Manager Rodney Iwashina -

Check what is listening on port 1743

Linux: is anything listening on TCP 1743?
sudo ss -tlnp 'sport = :1743'
Linux: UDP 1743
sudo ss -ulnp 'sport = :1743'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1743
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1743 '
Windows (Command Prompt)
netstat -ano | findstr :1743
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1743 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1743
From Windows
Test-NetConnection HOST -Port 1743
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1743

Block port 1743 in the firewall

ufw
sudo ufw deny 1743/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1743 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1743 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1743' -Direction Inbound -Protocol TCP -LocalPort 1743 -Action Block
ufw
sudo ufw deny 1743/udp
iptables
sudo iptables -A INPUT -p udp --dport 1743 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1743 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1743' -Direction Inbound -Protocol UDP -LocalPort 1743 -Action Block

Related ports

1741cisco-net-mgmt17423Com-nsd1744ncpm-ft1745remote-winsock

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