Port 3999

nvcnet · TCP/UDP

RangeRegistered port (1024–49151)
ProtocolTCP/UDP
Servicenvcnet
Registered2007-11-06

Frequently asked questions

What is port 3999 used for?

Port 3999 is registered with the IANA for nvcnet (TCP/UDP). Description: Norman distributes scanning service.

Is port 3999 a well-known port?

No. Port 3999 is in the range 1024–49151 (registered or user ports). Ordinary programs may open it without root privileges.

How do I check whether port 3999 is open?

Locally on Linux with ss -tulpn | grep ':3999\b', on Windows with netstat -ano | findstr :3999. To test a remote host use Test-NetConnection <host> -Port 3999 in PowerShell or nc -zv <host> 3999 on Linux/macOS.

How do I open port 3999 in the firewall?

Ubuntu/Debian (ufw): sudo ufw allow 3999/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=3999/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 3999" -Direction Inbound -Protocol TCP -LocalPort 3999 -Action Allow.

IANA registry entries

ProtocolServiceDescription (IANA)
TCPnvcnetNorman distributes scanning service
UDPnvcnetNorman distributes scanning service

Nearby entries