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Port 216 (CAIlic)

IANA assigns port 216 to CAIlic: Computer Associates Int'l License Server.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
CAIlic TCP Computer Associates Int'l License Server Chuck Spitz -
CAIlic UDP Computer Associates Int'l License Server Chuck Spitz -

Check what is listening on port 216

Linux: is anything listening on TCP 216?
sudo ss -tlnp 'sport = :216'
Linux: UDP 216
sudo ss -ulnp 'sport = :216'
Linux / macOS: which process owns the port
sudo lsof -nP -i :216
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':216 '
Windows (Command Prompt)
netstat -ano | findstr :216
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 216 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 216
From Windows
Test-NetConnection HOST -Port 216
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 216

Block port 216 in the firewall

ufw
sudo ufw deny 216/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 216 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 216 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 216' -Direction Inbound -Protocol TCP -LocalPort 216 -Action Block
ufw
sudo ufw deny 216/udp
iptables
sudo iptables -A INPUT -p udp --dport 216 -j DROP
nftables
sudo nft add rule inet filter input udp dport 216 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 216' -Direction Inbound -Protocol UDP -LocalPort 216 -Action Block

Related ports

214vmpwscs215softpc217dbase218mpp

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