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// Other services

Port 3866: Sun SDViz DZDAEMON Port

Port 3866 is assigned by IANA to dzdaemon (Sun SDViz DZDAEMON Port).

3866

How dzdaemon works

Other services
client:3866dzdaemonresponse client:3866dzdaemonresponse

The client sends a request to port 3866 and the dzdaemon 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 3866 dangerous?

We have no specific security note for port 3866. 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 3866

ServicePortTransportDescriptionReferenceUpdated
dzdaemon 3866 TCP, UDP Sun SDViz DZDAEMON Port - 2003-08

// source: IANA service name and port number registry

03 Check it

Which program uses port 3866, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3866'      # process listening on 3866
sudo lsof -nP -i :3866

macOS

sudo lsof -nP -i :3866

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3866 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3866
netstat -ano | findstr :3866

From another machine

nmap -p 3866 -sV <host>
sudo nmap -sU -p 3866 <host>
nc -zv <host> 3866

Block it in the firewall

sudo ufw deny 3866/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3866" -Direction Inbound -LocalPort 3866 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3866 used for?

Port 3866 is assigned by IANA to dzdaemon (Sun SDViz DZDAEMON Port).

Is port 3866 TCP or UDP?

Port 3866 is registered for TCP and UDP.

Is it safe to open port 3866?

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 3866 is open?

On Linux run "ss -ltnup 'sport = :3866'", on macOS "lsof -nP -i :3866", and on Windows "netstat -ano | findstr :3866" to see the local process. From another machine, "nmap -p 3866 <host>" shows whether it is reachable.

05 Related
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