CyberHunter
// Other services

Port 4559: HylaFAX

Port 4559 is assigned by IANA to hylafax (HylaFAX).

4559

How hylafax works

Other services
client:4559hylafaxresponse client:4559hylafaxresponse

The client sends a request to port 4559 and the hylafax 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 4559 dangerous?

We have no specific security note for port 4559. 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 4559

ServicePortTransportDescriptionReferenceUpdated
hylafax 4559 TCP, UDP HylaFAX - 2002-03

// source: IANA service name and port number registry

03 Check it

Which program uses port 4559, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4559'      # process listening on 4559
sudo lsof -nP -i :4559

macOS

sudo lsof -nP -i :4559

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4559 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4559
netstat -ano | findstr :4559

From another machine

nmap -p 4559 -sV <host>
sudo nmap -sU -p 4559 <host>
nc -zv <host> 4559

Block it in the firewall

sudo ufw deny 4559/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4559" -Direction Inbound -LocalPort 4559 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4559 used for?

Port 4559 is assigned by IANA to hylafax (HylaFAX).

Is port 4559 TCP or UDP?

Port 4559 is registered for TCP and UDP.

Is it safe to open port 4559?

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 4559 is open?

On Linux run "ss -ltnup 'sport = :4559'", on macOS "lsof -nP -i :4559", and on Windows "netstat -ano | findstr :4559" to see the local process. From another machine, "nmap -p 4559 <host>" shows whether it is reachable.

05 Related