HTTPfy

Port 489 (nest-protocol)

IANA assigns port 489 to nest-protocol.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
nest-protocol TCP nest-protocol Gilles Gameiro -
nest-protocol UDP nest-protocol Gilles Gameiro -

Check what is listening on port 489

Linux: is anything listening on TCP 489?
sudo ss -tlnp 'sport = :489'
Linux: UDP 489
sudo ss -ulnp 'sport = :489'
Linux / macOS: which process owns the port
sudo lsof -nP -i :489
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':489 '
Windows (Command Prompt)
netstat -ano | findstr :489
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 489 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 489
From Windows
Test-NetConnection HOST -Port 489
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 489

Block port 489 in the firewall

ufw
sudo ufw deny 489/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 489 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 489 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 489' -Direction Inbound -Protocol TCP -LocalPort 489 -Action Block
ufw
sudo ufw deny 489/udp
iptables
sudo iptables -A INPUT -p udp --dport 489 -j DROP
nftables
sudo nft add rule inet filter input udp dport 489 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 489' -Direction Inbound -Protocol UDP -LocalPort 489 -Action Block

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487saft488gss-http490micom-pfs491go-login

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