CyberHunter
// Other services

Port 189: Queued File Transport

Port 189 is assigned by IANA to qft (Queued File Transport).

189

How qft works

Other services
client:189qftresponse client:189qftresponse

The client sends a request to port 189 and the qft 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)
01 Security

Is port 189 dangerous?

We have no specific security note for port 189. 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 189

ServicePortTransportDescriptionReferenceUpdated
qft 189 TCP, UDP Queued File Transport - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 189, and is it reachable?

Linux

sudo ss -ltnup 'sport = :189'      # process listening on 189
sudo lsof -nP -i :189

macOS

sudo lsof -nP -i :189

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 189 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 189
netstat -ano | findstr :189

From another machine

nmap -p 189 -sV <host>
sudo nmap -sU -p 189 <host>
nc -zv <host> 189

Block it in the firewall

sudo ufw deny 189/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 189" -Direction Inbound -LocalPort 189 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 189 used for?

Port 189 is assigned by IANA to qft (Queued File Transport).

Is port 189 TCP or UDP?

Port 189 is registered for TCP and UDP.

Is it safe to open port 189?

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 189 is open?

On Linux run "ss -ltnup 'sport = :189'", on macOS "lsof -nP -i :189", and on Windows "netstat -ano | findstr :189" to see the local process. From another machine, "nmap -p 189 <host>" shows whether it is reachable.

05 Related