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Port 1400 (cadkey-tablet)

IANA assigns port 1400 to cadkey-tablet: Cadkey Tablet Daemon.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cadkey-tablet TCP Cadkey Tablet Daemon Joe McCollough -
cadkey-tablet UDP Cadkey Tablet Daemon Joe McCollough -

Check what is listening on port 1400

Linux: is anything listening on TCP 1400?
sudo ss -tlnp 'sport = :1400'
Linux: UDP 1400
sudo ss -ulnp 'sport = :1400'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1400
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1400 '
Windows (Command Prompt)
netstat -ano | findstr :1400
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1400 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1400
From Windows
Test-NetConnection HOST -Port 1400
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1400

Block port 1400 in the firewall

ufw
sudo ufw deny 1400/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1400 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1400 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1400' -Direction Inbound -Protocol TCP -LocalPort 1400 -Action Block
ufw
sudo ufw deny 1400/udp
iptables
sudo iptables -A INPUT -p udp --dport 1400 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1400 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1400' -Direction Inbound -Protocol UDP -LocalPort 1400 -Action Block

Related ports

1398video-activmail1399cadkey-licman1401goldleaf-licman1402prm-sm-np

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