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Port 3555 (razor)

IANA assigns port 3555 to razor: Vipul's Razor.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
razor TCP Vipul's Razor Vipul Ved Prakash -
razor UDP Vipul's Razor Vipul Ved Prakash -

Registry dates for this port: registered 2002-07.

Check what is listening on port 3555

Linux: is anything listening on TCP 3555?
sudo ss -tlnp 'sport = :3555'
Linux: UDP 3555
sudo ss -ulnp 'sport = :3555'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3555
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3555 '
Windows (Command Prompt)
netstat -ano | findstr :3555
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3555 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3555
From Windows
Test-NetConnection HOST -Port 3555
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3555

Block port 3555 in the firewall

ufw
sudo ufw deny 3555/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3555 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3555 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3555' -Direction Inbound -Protocol TCP -LocalPort 3555 -Action Block
ufw
sudo ufw deny 3555/udp
iptables
sudo iptables -A INPUT -p udp --dport 3555 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3555 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3555' -Direction Inbound -Protocol UDP -LocalPort 3555 -Action Block

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3553rbr-discovery3554questnotify3556sky-transport3557personalos-001

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