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Port 402 (genie)

IANA assigns port 402 to genie: Genie Protocol.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
genie TCP Genie Protocol Mark Hankin -
genie UDP Genie Protocol Mark Hankin -

Check what is listening on port 402

Linux: is anything listening on TCP 402?
sudo ss -tlnp 'sport = :402'
Linux: UDP 402
sudo ss -ulnp 'sport = :402'
Linux / macOS: which process owns the port
sudo lsof -nP -i :402
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':402 '
Windows (Command Prompt)
netstat -ano | findstr :402
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 402 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 402
From Windows
Test-NetConnection HOST -Port 402
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 402

Block port 402 in the firewall

ufw
sudo ufw deny 402/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 402 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 402 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 402' -Direction Inbound -Protocol TCP -LocalPort 402 -Action Block
ufw
sudo ufw deny 402/udp
iptables
sudo iptables -A INPUT -p udp --dport 402 -j DROP
nftables
sudo nft add rule inet filter input udp dport 402 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 402' -Direction Inbound -Protocol UDP -LocalPort 402 -Action Block

Related ports

400osb-sd401ups403decap404nced

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