Port 2201 (ats)

IANA assigns port 2201 to ats: Advanced Training System Program.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

ats TCP Advanced Training System Program - -

ats UDP Advanced Training System Program - -

Linux: is anything listening on TCP 2201?

sudo ss -tlnp 'sport = :2201'

Linux: UDP 2201

sudo ss -ulnp 'sport = :2201'

Linux / macOS: which process owns the port

sudo lsof -nP -i :2201

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':2201 '

Windows (Command Prompt)

netstat -ano | findstr :2201

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2201 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 2201

From Windows

Test-NetConnection HOST -Port 2201

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 2201

ufw

sudo ufw deny 2201/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 2201 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 2201 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 2201' -Direction Inbound -Protocol TCP -LocalPort 2201 -Action Block

ufw

sudo ufw deny 2201/udp

iptables

sudo iptables -A INPUT -p udp --dport 2201 -j DROP

nftables

sudo nft add rule inet filter input udp dport 2201 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 2201' -Direction Inbound -Protocol UDP -LocalPort 2201 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.