CyberHunter
// Voice & chat

Port 3447: DirectNet IM System

Port 3447 is assigned by IANA to directnet (DirectNet IM System).

3447

How directnet works

Voice & chat
callercalleedirectnet callercalleedirectnet

Port 3447 sets up the call (who calls whom), then the voice travels as a stream of audio packets.

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
Voice & chat
01 Security

Is port 3447 dangerous?

We have no specific security note for port 3447. Its risk depends on the program actually listening on it. General advice for voice & chat services:

  • Use strong credentials and TLS for signalling.
  • Rate-limit registrations to stop extension scanning and toll fraud.
  • Alert on unexpected chat protocols leaving servers (possible command and control).
02 Registry

IANA registry entries for port 3447

ServicePortTransportDescriptionReferenceUpdated
directnet 3447 TCP, UDP DirectNet IM System - 2002-04

// source: IANA service name and port number registry

03 Check it

Which program uses port 3447, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3447'      # process listening on 3447
sudo lsof -nP -i :3447

macOS

sudo lsof -nP -i :3447

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3447 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3447
netstat -ano | findstr :3447

From another machine

nmap -p 3447 -sV <host>
sudo nmap -sU -p 3447 <host>
nc -zv <host> 3447

Block it in the firewall

sudo ufw deny 3447/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3447" -Direction Inbound -LocalPort 3447 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3447 used for?

Port 3447 is assigned by IANA to directnet (DirectNet IM System).

Is port 3447 TCP or UDP?

Port 3447 is registered for TCP and UDP.

Is it safe to open port 3447?

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. Use strong credentials and TLS for signalling.

How do I check if port 3447 is open?

On Linux run "ss -ltnup 'sport = :3447'", on macOS "lsof -nP -i :3447", and on Windows "netstat -ano | findstr :3447" to see the local process. From another machine, "nmap -p 3447 <host>" shows whether it is reachable.

05 Related