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// Other services

Port 509: snare

Port 509 is assigned by IANA to snare (snare).

509

How snare works

Other services
client:509snareresponse client:509snareresponse

The client sends a request to port 509 and the snare 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
Well-known (0-1023)
Category
Other services
01 Security

Is port 509 dangerous?

We have no specific security note for port 509. 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 509

ServicePortTransportDescriptionReferenceUpdated
snare 509 TCP, UDP snare - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 509, and is it reachable?

Linux

sudo ss -ltnup 'sport = :509'      # process listening on 509
sudo lsof -nP -i :509

macOS

sudo lsof -nP -i :509

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 509 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 509
netstat -ano | findstr :509

From another machine

nmap -p 509 -sV <host>
sudo nmap -sU -p 509 <host>
nc -zv <host> 509

Block it in the firewall

sudo ufw deny 509/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 509" -Direction Inbound -LocalPort 509 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 509 used for?

Port 509 is assigned by IANA to snare (snare).

Is port 509 TCP or UDP?

Port 509 is registered for TCP and UDP.

Is it safe to open port 509?

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 509 is open?

On Linux run "ss -ltnup 'sport = :509'", on macOS "lsof -nP -i :509", and on Windows "netstat -ano | findstr :509" to see the local process. From another machine, "nmap -p 509 <host>" shows whether it is reachable.

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