Port 1989 (tr-rsrb-p3, mshnet)

IANA assigns port 1989 to tr-rsrb-p3, mshnet: cisco RSRB Priority 3 port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

tr-rsrb-p3 TCP cisco RSRB Priority 3 port - -

mshnet TCP MHSnet system
This entry records an unassigned but widespread use Bob Kummerfeld -

tr-rsrb-p3 UDP cisco RSRB Priority 3 port - -

mshnet UDP MHSnet system
This entry records an unassigned but widespread use Bob Kummerfeld -

Linux: is anything listening on TCP 1989?

sudo ss -tlnp 'sport = :1989'

Linux: UDP 1989

sudo ss -ulnp 'sport = :1989'

Linux / macOS: which process owns the port

sudo lsof -nP -i :1989

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':1989 '

Windows (Command Prompt)

netstat -ano | findstr :1989

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1989 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 1989

From Windows

Test-NetConnection HOST -Port 1989

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

nc -vzu -w 5 HOST 1989

ufw

sudo ufw deny 1989/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 1989 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 1989 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 1989' -Direction Inbound -Protocol TCP -LocalPort 1989 -Action Block

ufw

sudo ufw deny 1989/udp

iptables

sudo iptables -A INPUT -p udp --dport 1989 -j DROP

nftables

sudo nft add rule inet filter input udp dport 1989 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 1989' -Direction Inbound -Protocol UDP -LocalPort 1989 -Action Block

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