CyberHunter
Local dataset, no network
// Other services

Port 507: crs

Port 507 is assigned by IANA to crs (crs).

507

How crs works

Other services
client:507crsresponse client:507crsresponse

The client sends a request to port 507 and the crs 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 507 dangerous?

We have no specific security note for port 507. 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 507

ServicePortTransportDescriptionReferenceUpdated
crs 507 TCP, UDP crs - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 507, and is it reachable?

Linux

sudo ss -ltnup 'sport = :507'      # process listening on 507
sudo lsof -nP -i :507

macOS

sudo lsof -nP -i :507

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 507 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 507
netstat -ano | findstr :507

From another machine

nmap -p 507 -sV <host>
sudo nmap -sU -p 507 <host>
nc -zv <host> 507

Block it in the firewall

sudo ufw deny 507/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 507" -Direction Inbound -LocalPort 507 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 507 used for?

Port 507 is assigned by IANA to crs (crs).

Is port 507 TCP or UDP?

Port 507 is registered for TCP and UDP.

Is it safe to open port 507?

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 507 is open?

On Linux run "ss -ltnup 'sport = :507'", on macOS "lsof -nP -i :507", and on Windows "netstat -ano | findstr :507" to see the local process. From another machine, "nmap -p 507 <host>" shows whether it is reachable.

05 Related
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