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// Other services

Port 3603: Integrated Rcvr Control

Port 3603 is assigned by IANA to int-rcv-cntrl (Integrated Rcvr Control).

3603

How int-rcv-cntrl works

Other services
client:3603int-rcv-cntrlresponse client:3603int-rcv-cntrlresponse

The client sends a request to port 3603 and the int-rcv-cntrl 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 3603 dangerous?

We have no specific security note for port 3603. 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 3603

ServicePortTransportDescriptionReferenceUpdated
int-rcv-cntrl 3603 TCP, UDP Integrated Rcvr Control - 2002-09

// source: IANA service name and port number registry

03 Check it

Which program uses port 3603, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3603'      # process listening on 3603
sudo lsof -nP -i :3603

macOS

sudo lsof -nP -i :3603

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3603 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3603
netstat -ano | findstr :3603

From another machine

nmap -p 3603 -sV <host>
sudo nmap -sU -p 3603 <host>
nc -zv <host> 3603

Block it in the firewall

sudo ufw deny 3603/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3603" -Direction Inbound -LocalPort 3603 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3603 used for?

Port 3603 is assigned by IANA to int-rcv-cntrl (Integrated Rcvr Control).

Is port 3603 TCP or UDP?

Port 3603 is registered for TCP and UDP.

Is it safe to open port 3603?

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 3603 is open?

On Linux run "ss -ltnup 'sport = :3603'", on macOS "lsof -nP -i :3603", and on Windows "netstat -ano | findstr :3603" to see the local process. From another machine, "nmap -p 3603 <host>" shows whether it is reachable.

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