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// Other services

Port 8766: Agilent Connectivity Service

Port 8766 is assigned by IANA to amcs (Agilent Connectivity Service).

8766

How amcs works

Other services
client:8766amcsresponse client:8766amcsresponse

The client sends a request to port 8766 and the amcs 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)
Category
Other services
01 Security

Is port 8766 dangerous?

We have no specific security note for port 8766. 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 8766

ServicePortTransportDescriptionReferenceUpdated
amcs 8766 TCP, UDP Agilent Connectivity Service - 2016-09-12

// source: IANA service name and port number registry

03 Check it

Which program uses port 8766, and is it reachable?

Linux

sudo ss -ltnup 'sport = :8766'      # process listening on 8766
sudo lsof -nP -i :8766

macOS

sudo lsof -nP -i :8766

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 8766 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 8766
netstat -ano | findstr :8766

From another machine

nmap -p 8766 -sV <host>
sudo nmap -sU -p 8766 <host>
nc -zv <host> 8766

Block it in the firewall

sudo ufw deny 8766/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 8766" -Direction Inbound -LocalPort 8766 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 8766 used for?

Port 8766 is assigned by IANA to amcs (Agilent Connectivity Service).

Is port 8766 TCP or UDP?

Port 8766 is registered for TCP and UDP.

Is it safe to open port 8766?

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 8766 is open?

On Linux run "ss -ltnup 'sport = :8766'", on macOS "lsof -nP -i :8766", and on Windows "netstat -ano | findstr :8766" to see the local process. From another machine, "nmap -p 8766 <host>" shows whether it is reachable.

05 Related
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