CyberHunter
Local dataset, no network
// Other services

Port 3928: PXE NetBoot Manager

Port 3928 is assigned by IANA to netboot-pxe (PXE NetBoot Manager).

3928

How netboot-pxe works

Other services
client:3928netboot-pxeresponse client:3928netboot-pxeresponse

The client sends a request to port 3928 and the netboot-pxe service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 3928 dangerous?

We have no specific security note for port 3928. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 3928

ServicePortTransportDescriptionReferenceUpdated
netboot-pxe 3928 TCP, UDP PXE NetBoot Manager - 2003-11

// source: IANA service name and port number registry

03 Check it

Which program uses port 3928, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3928'      # process listening on 3928
sudo lsof -nP -i :3928

macOS

sudo lsof -nP -i :3928

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3928 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3928
netstat -ano | findstr :3928

From another machine

nmap -p 3928 -sV <host>
sudo nmap -sU -p 3928 <host>
nc -zv <host> 3928

Block it in the firewall

sudo ufw deny 3928/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3928" -Direction Inbound -LocalPort 3928 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3928 used for?

Port 3928 is assigned by IANA to netboot-pxe (PXE NetBoot Manager).

Is port 3928 TCP or UDP?

Port 3928 is registered for TCP and UDP.

Is it safe to open port 3928?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 3928 is open?

On Linux run "ss -ltnup 'sport = :3928'", on macOS "lsof -nP -i :3928", and on Windows "netstat -ano | findstr :3928" to see the local process. From another machine, "nmap -p 3928 <host>" shows whether it is reachable.

05 Related
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