Port 1658 (sixnetudr)

IANA assigns port 1658 to sixnetudr.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

sixnetudr TCP sixnetudr Red Lion Controls -

sixnetudr UDP sixnetudr Red Lion Controls -

Registry dates for this port: last modified 2014-05-21.

Linux: is anything listening on TCP 1658?

sudo ss -tlnp 'sport = :1658'

Linux: UDP 1658

sudo ss -ulnp 'sport = :1658'

Linux / macOS: which process owns the port

sudo lsof -nP -i :1658

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':1658 '

Windows (Command Prompt)

netstat -ano | findstr :1658

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1658 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 1658

From Windows

Test-NetConnection HOST -Port 1658

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

nc -vzu -w 5 HOST 1658

ufw

sudo ufw deny 1658/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 1658 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 1658 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 1658' -Direction Inbound -Protocol TCP -LocalPort 1658 -Action Block

ufw

sudo ufw deny 1658/udp

iptables

sudo iptables -A INPUT -p udp --dport 1658 -j DROP

nftables

sudo nft add rule inet filter input udp dport 1658 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 1658' -Direction Inbound -Protocol UDP -LocalPort 1658 -Action Block

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