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Port 1940 (jvclient)

IANA assigns port 1940 to jvclient: JetVision Client Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
jvclient TCP JetVision Client Port Stephen Tsun -
jvclient UDP JetVision Client Port Stephen Tsun -

Check what is listening on port 1940

Linux: is anything listening on TCP 1940?
sudo ss -tlnp 'sport = :1940'
Linux: UDP 1940
sudo ss -ulnp 'sport = :1940'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1940
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1940 '
Windows (Command Prompt)
netstat -ano | findstr :1940
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1940 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1940
From Windows
Test-NetConnection HOST -Port 1940
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1940

Block port 1940 in the firewall

ufw
sudo ufw deny 1940/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1940 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1940 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1940' -Direction Inbound -Protocol TCP -LocalPort 1940 -Action Block
ufw
sudo ufw deny 1940/udp
iptables
sudo iptables -A INPUT -p udp --dport 1940 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1940 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1940' -Direction Inbound -Protocol UDP -LocalPort 1940 -Action Block

Related ports

1938jwclient1939jvserver1941dic-aida1942res

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