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Local dataset, no network
// Other services

Port 623: ASF Remote Management and Control Protocol

Port 623 is assigned by IANA to asf-rmcp (ASF Remote Management and Control Protocol), oob-ws-http (DMTF out-of-band web services management protocol).

623

How asf-rmcp works

Other services
client:623asf-rmcpresponse client:623asf-rmcpresponse

The client sends a request to port 623 and the asf-rmcp service answers.

Transport
UDP · TCP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned2 registered services
Range
Well-known (0-1023)
Category
Other services
01 Security

Is port 623 dangerous?

We have no specific security note for port 623. 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 623

ServicePortTransportDescriptionReferenceUpdated
asf-rmcp 623 UDP ASF Remote Management and Control Protocol - -
oob-ws-http 623 TCP DMTF out-of-band web services management protocol - 2007-06

// source: IANA service name and port number registry

03 Check it

Which program uses port 623, and is it reachable?

Linux

sudo ss -ltnup 'sport = :623'      # process listening on 623
sudo lsof -nP -i :623

macOS

sudo lsof -nP -i :623

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 623 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 623
netstat -ano | findstr :623

From another machine

nmap -p 623 -sV <host>
sudo nmap -sU -p 623 <host>
nc -zv <host> 623

Block it in the firewall

sudo ufw deny 623/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 623" -Direction Inbound -LocalPort 623 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 623 used for?

Port 623 is assigned by IANA to asf-rmcp (ASF Remote Management and Control Protocol), oob-ws-http (DMTF out-of-band web services management protocol).

Is port 623 TCP or UDP?

Port 623 is registered for UDP and TCP.

Is it safe to open port 623?

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 623 is open?

On Linux run "ss -ltnup 'sport = :623'", on macOS "lsof -nP -i :623", and on Windows "netstat -ano | findstr :623" to see the local process. From another machine, "nmap -p 623 <host>" shows whether it is reachable.

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