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// Other services

Port 8403: admind

Port 8403 is assigned by IANA to admind (admind).

8403

How admind works

Other services
client:8403admindresponse client:8403admindresponse

The client sends a request to port 8403 and the admind 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 8403 dangerous?

We have no specific security note for port 8403. 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 8403

ServicePortTransportDescriptionReferenceUpdated
admind 8403 TCP, UDP admind - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 8403, and is it reachable?

Linux

sudo ss -ltnup 'sport = :8403'      # process listening on 8403
sudo lsof -nP -i :8403

macOS

sudo lsof -nP -i :8403

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 8403 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 8403
netstat -ano | findstr :8403

From another machine

nmap -p 8403 -sV <host>
sudo nmap -sU -p 8403 <host>
nc -zv <host> 8403

Block it in the firewall

sudo ufw deny 8403/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 8403" -Direction Inbound -LocalPort 8403 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 8403 used for?

Port 8403 is assigned by IANA to admind (admind).

Is port 8403 TCP or UDP?

Port 8403 is registered for TCP and UDP.

Is it safe to open port 8403?

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 8403 is open?

On Linux run "ss -ltnup 'sport = :8403'", on macOS "lsof -nP -i :8403", and on Windows "netstat -ano | findstr :8403" to see the local process. From another machine, "nmap -p 8403 <host>" shows whether it is reachable.

05 Related
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