CyberHunter
Local dataset, no network
// Other services

Port 2104: Zephyr hostmanager

Port 2104 is assigned by IANA to zephyr-hm (Zephyr hostmanager).

2104

How zephyr-hm works

Other services
client:2104zephyr-hmresponse client:2104zephyr-hmresponse

The client sends a request to port 2104 and the zephyr-hm 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 2104 dangerous?

We have no specific security note for port 2104. 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 2104

ServicePortTransportDescriptionReferenceUpdated
zephyr-hm 2104 TCP, UDP Zephyr hostmanager - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2104, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2104'      # process listening on 2104
sudo lsof -nP -i :2104

macOS

sudo lsof -nP -i :2104

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2104 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2104
netstat -ano | findstr :2104

From another machine

nmap -p 2104 -sV <host>
sudo nmap -sU -p 2104 <host>
nc -zv <host> 2104

Block it in the firewall

sudo ufw deny 2104/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2104" -Direction Inbound -LocalPort 2104 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2104 used for?

Port 2104 is assigned by IANA to zephyr-hm (Zephyr hostmanager).

Is port 2104 TCP or UDP?

Port 2104 is registered for TCP and UDP.

Is it safe to open port 2104?

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 2104 is open?

On Linux run "ss -ltnup 'sport = :2104'", on macOS "lsof -nP -i :2104", and on Windows "netstat -ano | findstr :2104" to see the local process. From another machine, "nmap -p 2104 <host>" shows whether it is reachable.

05 Related

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