Port 19998 (iec-104-sec)

IANA assigns port 19998 to iec-104-sec: IEC 60870-5-104 process control - secure.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference

iec-104-sec TCP IEC 60870-5-104 process control - secure Grant Gilchrist -

Registry dates for this port: registered 2010-10-18.

Linux: is anything listening on TCP 19998?

sudo ss -tlnp 'sport = :19998'

Linux / macOS: which process owns the port

sudo lsof -nP -i :19998

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':19998 '

Windows (Command Prompt)

netstat -ano | findstr :19998

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 19998 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 19998

From Windows

Test-NetConnection HOST -Port 19998

ufw

sudo ufw deny 19998/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 19998 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 19998 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 19998' -Direction Inbound -Protocol TCP -LocalPort 19998 -Action Block

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