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// Other services

Port 671: VACDSM-APP

Port 671 is assigned by IANA to vacdsm-app (VACDSM-APP).

671

How vacdsm-app works

Other services
client:671vacdsm-appresponse client:671vacdsm-appresponse

The client sends a request to port 671 and the vacdsm-app 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 671 dangerous?

We have no specific security note for port 671. 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 671

ServicePortTransportDescriptionReferenceUpdated
vacdsm-app 671 TCP, UDP VACDSM-APP - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 671, and is it reachable?

Linux

sudo ss -ltnup 'sport = :671'      # process listening on 671
sudo lsof -nP -i :671

macOS

sudo lsof -nP -i :671

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 671 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 671
netstat -ano | findstr :671

From another machine

nmap -p 671 -sV <host>
sudo nmap -sU -p 671 <host>
nc -zv <host> 671

Block it in the firewall

sudo ufw deny 671/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 671" -Direction Inbound -LocalPort 671 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 671 used for?

Port 671 is assigned by IANA to vacdsm-app (VACDSM-APP).

Is port 671 TCP or UDP?

Port 671 is registered for TCP and UDP.

Is it safe to open port 671?

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 671 is open?

On Linux run "ss -ltnup 'sport = :671'", on macOS "lsof -nP -i :671", and on Windows "netstat -ano | findstr :671" to see the local process. From another machine, "nmap -p 671 <host>" shows whether it is reachable.

05 Related
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