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// Other services

Port 5503: fcp-srvr-inst2

Port 5503 is assigned by IANA to fcp-srvr-inst2 (fcp-srvr-inst2).

5503

How fcp-srvr-inst2 works

Other services
client:5503fcp-srvr-inst2response client:5503fcp-srvr-inst2response

The client sends a request to port 5503 and the fcp-srvr-inst2 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 5503 dangerous?

We have no specific security note for port 5503. 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 5503

ServicePortTransportDescriptionReferenceUpdated
fcp-srvr-inst2 5503 TCP, UDP fcp-srvr-inst2 - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 5503, and is it reachable?

Linux

sudo ss -ltnup 'sport = :5503'      # process listening on 5503
sudo lsof -nP -i :5503

macOS

sudo lsof -nP -i :5503

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 5503 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 5503
netstat -ano | findstr :5503

From another machine

nmap -p 5503 -sV <host>
sudo nmap -sU -p 5503 <host>
nc -zv <host> 5503

Block it in the firewall

sudo ufw deny 5503/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 5503" -Direction Inbound -LocalPort 5503 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 5503 used for?

Port 5503 is assigned by IANA to fcp-srvr-inst2 (fcp-srvr-inst2).

Is port 5503 TCP or UDP?

Port 5503 is registered for TCP and UDP.

Is it safe to open port 5503?

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 5503 is open?

On Linux run "ss -ltnup 'sport = :5503'", on macOS "lsof -nP -i :5503", and on Windows "netstat -ano | findstr :5503" to see the local process. From another machine, "nmap -p 5503 <host>" shows whether it is reachable.

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