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// Other services

Port 3390: Distributed Service Coordinator

Port 3390 is assigned by IANA to dsc (Distributed Service Coordinator).

3390

How dsc works

Other services
client:3390dscresponse client:3390dscresponse

The client sends a request to port 3390 and the dsc 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 3390 dangerous?

We have no specific security note for port 3390. 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 3390

ServicePortTransportDescriptionReferenceUpdated
dsc 3390 TCP, UDP Distributed Service Coordinator - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 3390, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3390'      # process listening on 3390
sudo lsof -nP -i :3390

macOS

sudo lsof -nP -i :3390

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3390 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3390
netstat -ano | findstr :3390

From another machine

nmap -p 3390 -sV <host>
sudo nmap -sU -p 3390 <host>
nc -zv <host> 3390

Block it in the firewall

sudo ufw deny 3390/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3390" -Direction Inbound -LocalPort 3390 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3390 used for?

Port 3390 is assigned by IANA to dsc (Distributed Service Coordinator).

Is port 3390 TCP or UDP?

Port 3390 is registered for TCP and UDP.

Is it safe to open port 3390?

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 3390 is open?

On Linux run "ss -ltnup 'sport = :3390'", on macOS "lsof -nP -i :3390", and on Windows "netstat -ano | findstr :3390" to see the local process. From another machine, "nmap -p 3390 <host>" shows whether it is reachable.

05 Related
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