CyberHunter
// Other services

Port 2101: rtcm-sc104

Port 2101 is assigned by IANA to rtcm-sc104 (rtcm-sc104).

2101

How rtcm-sc104 works

Other services
client:2101rtcm-sc104response client:2101rtcm-sc104response

The client sends a request to port 2101 and the rtcm-sc104 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)
01 Security

Is port 2101 dangerous?

We have no specific security note for port 2101. 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 2101

ServicePortTransportDescriptionReferenceUpdated
rtcm-sc104 2101 TCP, UDP rtcm-sc104 - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2101, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2101'      # process listening on 2101
sudo lsof -nP -i :2101

macOS

sudo lsof -nP -i :2101

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2101 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2101
netstat -ano | findstr :2101

From another machine

nmap -p 2101 -sV <host>
sudo nmap -sU -p 2101 <host>
nc -zv <host> 2101

Block it in the firewall

sudo ufw deny 2101/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2101" -Direction Inbound -LocalPort 2101 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2101 used for?

Port 2101 is assigned by IANA to rtcm-sc104 (rtcm-sc104).

Is port 2101 TCP or UDP?

Port 2101 is registered for TCP and UDP.

Is it safe to open port 2101?

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 2101 is open?

On Linux run "ss -ltnup 'sport = :2101'", on macOS "lsof -nP -i :2101", and on Windows "netstat -ano | findstr :2101" to see the local process. From another machine, "nmap -p 2101 <host>" shows whether it is reachable.

05 Related