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Port 4663 (noteit)

IANA assigns port 4663 to noteit: Note It! Message Service.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
noteit TCP Note It! Message Service Pedro Alpedrinha -
noteit UDP Note It! Message Service Pedro Alpedrinha -

Registry dates for this port: registered 2006-02.

Check what is listening on port 4663

Linux: is anything listening on TCP 4663?
sudo ss -tlnp 'sport = :4663'
Linux: UDP 4663
sudo ss -ulnp 'sport = :4663'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4663
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4663 '
Windows (Command Prompt)
netstat -ano | findstr :4663
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4663 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4663
From Windows
Test-NetConnection HOST -Port 4663
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4663

Block port 4663 in the firewall

ufw
sudo ufw deny 4663/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4663 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4663 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4663' -Direction Inbound -Protocol TCP -LocalPort 4663 -Action Block
ufw
sudo ufw deny 4663/udp
iptables
sudo iptables -A INPUT -p udp --dport 4663 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4663 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4663' -Direction Inbound -Protocol UDP -LocalPort 4663 -Action Block

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