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// Other services

Port 6550: fg-sysupdate

Port 6550 is assigned by IANA to fg-sysupdate (fg-sysupdate).

6550

How fg-sysupdate works

Other services
client:6550fg-sysupdateresponse client:6550fg-sysupdateresponse

The client sends a request to port 6550 and the fg-sysupdate 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 6550 dangerous?

We have no specific security note for port 6550. 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 6550

ServicePortTransportDescriptionReferenceUpdated
fg-sysupdate 6550 TCP, UDP fg-sysupdate - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 6550, and is it reachable?

Linux

sudo ss -ltnup 'sport = :6550'      # process listening on 6550
sudo lsof -nP -i :6550

macOS

sudo lsof -nP -i :6550

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6550 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 6550
netstat -ano | findstr :6550

From another machine

nmap -p 6550 -sV <host>
sudo nmap -sU -p 6550 <host>
nc -zv <host> 6550

Block it in the firewall

sudo ufw deny 6550/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 6550" -Direction Inbound -LocalPort 6550 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 6550 used for?

Port 6550 is assigned by IANA to fg-sysupdate (fg-sysupdate).

Is port 6550 TCP or UDP?

Port 6550 is registered for TCP and UDP.

Is it safe to open port 6550?

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 6550 is open?

On Linux run "ss -ltnup 'sport = :6550'", on macOS "lsof -nP -i :6550", and on Windows "netstat -ano | findstr :6550" to see the local process. From another machine, "nmap -p 6550 <host>" shows whether it is reachable.

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