CyberHunter
Local dataset, no network
// Other services

Port 439: dasp

Port 439 is assigned by IANA to dasp (dasp).

439

How dasp works

Other services
client:439daspresponse client:439daspresponse

The client sends a request to port 439 and the dasp 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
Well-known (0-1023)
Category
Other services
01 Security

Is port 439 dangerous?

We have no specific security note for port 439. 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 439

ServicePortTransportDescriptionReferenceUpdated
dasp 439 TCP, UDP dasp - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 439, and is it reachable?

Linux

sudo ss -ltnup 'sport = :439'      # process listening on 439
sudo lsof -nP -i :439

macOS

sudo lsof -nP -i :439

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 439 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 439
netstat -ano | findstr :439

From another machine

nmap -p 439 -sV <host>
sudo nmap -sU -p 439 <host>
nc -zv <host> 439

Block it in the firewall

sudo ufw deny 439/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 439" -Direction Inbound -LocalPort 439 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 439 used for?

Port 439 is assigned by IANA to dasp (dasp).

Is port 439 TCP or UDP?

Port 439 is registered for TCP and UDP.

Is it safe to open port 439?

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 439 is open?

On Linux run "ss -ltnup 'sport = :439'", on macOS "lsof -nP -i :439", and on Windows "netstat -ano | findstr :439" to see the local process. From another machine, "nmap -p 439 <host>" shows whether it is reachable.

05 Related
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