Port 16021 (jwpc-bin)

IANA assigns port 16021 to jwpc-bin: Filemaker Java Web Publishing Core Binary.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference

jwpc-bin TCP Filemaker Java Web Publishing Core Binary Robert Parks -

Registry dates for this port: registered 2010-05-12.

Linux: is anything listening on TCP 16021?

sudo ss -tlnp 'sport = :16021'

Linux / macOS: which process owns the port

sudo lsof -nP -i :16021

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':16021 '

Windows (Command Prompt)

netstat -ano | findstr :16021

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 16021 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 16021

From Windows

Test-NetConnection HOST -Port 16021

ufw

sudo ufw deny 16021/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 16021 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 16021 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 16021' -Direction Inbound -Protocol TCP -LocalPort 16021 -Action Block

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