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Port 3557 (personalos-001)

IANA assigns port 3557 to personalos-001: PersonalOS Comm Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
personalos-001 TCP PersonalOS Comm Port Shane Roberts -
personalos-001 UDP PersonalOS Comm Port Shane Roberts -

Registry dates for this port: registered 2002-07.

Check what is listening on port 3557

Linux: is anything listening on TCP 3557?
sudo ss -tlnp 'sport = :3557'
Linux: UDP 3557
sudo ss -ulnp 'sport = :3557'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3557
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3557 '
Windows (Command Prompt)
netstat -ano | findstr :3557
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3557 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3557
From Windows
Test-NetConnection HOST -Port 3557
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3557

Block port 3557 in the firewall

ufw
sudo ufw deny 3557/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3557 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3557 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3557' -Direction Inbound -Protocol TCP -LocalPort 3557 -Action Block
ufw
sudo ufw deny 3557/udp
iptables
sudo iptables -A INPUT -p udp --dport 3557 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3557 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3557' -Direction Inbound -Protocol UDP -LocalPort 3557 -Action Block

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3555razor3556sky-transport3558mcp-port3559cctv-port

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