CyberHunter
Local dataset, no network
// Other services

Port 21010: Notezilla.Lan Server

Port 21010 is assigned by IANA to notezilla-lan (Notezilla.Lan Server).

21010

How notezilla-lan works

Other services
client:21010notezilla-lanresponse client:21010notezilla-lanresponse

The client sends a request to port 21010 and the notezilla-lan service answers.

Transport
TCP
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 21010 dangerous?

We have no specific security note for port 21010. 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 21010

ServicePortTransportDescriptionReferenceUpdated
notezilla-lan 21010 TCP Notezilla.Lan Server - 2013-08-20
-21010-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 21010, and is it reachable?

Linux

sudo ss -ltnup 'sport = :21010'      # process listening on 21010
sudo lsof -nP -i :21010

macOS

sudo lsof -nP -i :21010

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 21010 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 21010
netstat -ano | findstr :21010

From another machine

nmap -p 21010 -sV <host>
nc -zv <host> 21010

Block it in the firewall

sudo ufw deny 21010/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 21010" -Direction Inbound -LocalPort 21010 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 21010 used for?

Port 21010 is assigned by IANA to notezilla-lan (Notezilla.Lan Server).

Is port 21010 TCP or UDP?

Port 21010 is registered for TCP.

Is it safe to open port 21010?

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 21010 is open?

On Linux run "ss -ltnup 'sport = :21010'", on macOS "lsof -nP -i :21010", and on Windows "netstat -ano | findstr :21010" to see the local process. From another machine, "nmap -p 21010 <host>" shows whether it is reachable.

05 Related
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