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// Other services

Port 2321: RDLAP

Port 2321 is assigned by IANA to rdlap (RDLAP).

2321

How rdlap works

Other services
client:2321rdlapresponse client:2321rdlapresponse

The client sends a request to port 2321 and the rdlap 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 2321 dangerous?

We have no specific security note for port 2321. 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 2321

ServicePortTransportDescriptionReferenceUpdated
rdlap 2321 TCP, UDP RDLAP - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2321, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2321'      # process listening on 2321
sudo lsof -nP -i :2321

macOS

sudo lsof -nP -i :2321

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2321 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2321
netstat -ano | findstr :2321

From another machine

nmap -p 2321 -sV <host>
sudo nmap -sU -p 2321 <host>
nc -zv <host> 2321

Block it in the firewall

sudo ufw deny 2321/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2321" -Direction Inbound -LocalPort 2321 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2321 used for?

Port 2321 is assigned by IANA to rdlap (RDLAP).

Is port 2321 TCP or UDP?

Port 2321 is registered for TCP and UDP.

Is it safe to open port 2321?

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 2321 is open?

On Linux run "ss -ltnup 'sport = :2321'", on macOS "lsof -nP -i :2321", and on Windows "netstat -ano | findstr :2321" to see the local process. From another machine, "nmap -p 2321 <host>" shows whether it is reachable.

05 Related
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