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Port 22001 (optocontrol)

IANA assigns port 22001 to optocontrol: OptoControl.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
optocontrol TCP OptoControl Kevin Kuhns -
optocontrol UDP OptoControl Kevin Kuhns -

Check what is listening on port 22001

Linux: is anything listening on TCP 22001?
sudo ss -tlnp 'sport = :22001'
Linux: UDP 22001
sudo ss -ulnp 'sport = :22001'
Linux / macOS: which process owns the port
sudo lsof -nP -i :22001
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':22001 '
Windows (Command Prompt)
netstat -ano | findstr :22001
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 22001 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 22001
From Windows
Test-NetConnection HOST -Port 22001
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 22001

Block port 22001 in the firewall

ufw
sudo ufw deny 22001/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 22001 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 22001 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 22001' -Direction Inbound -Protocol TCP -LocalPort 22001 -Action Block
ufw
sudo ufw deny 22001/udp
iptables
sudo iptables -A INPUT -p udp --dport 22001 -j DROP
nftables
sudo nft add rule inet filter input udp dport 22001 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 22001' -Direction Inbound -Protocol UDP -LocalPort 22001 -Action Block

Related ports

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