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// Other services

Port 6687: CleverView for cTrace Message Service

Port 6687 is assigned by IANA to clever-ctrace (CleverView for cTrace Message Service).

6687

How clever-ctrace works

Other services
client:6687clever-ctraceresponse client:6687clever-ctraceresponse

The client sends a request to port 6687 and the clever-ctrace service answers.

Transport
TCP
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 6687 dangerous?

We have no specific security note for port 6687. 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 6687

ServicePortTransportDescriptionReferenceUpdated
clever-ctrace 6687 TCP CleverView for cTrace Message Service - 2010-02-01
-6687-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 6687, and is it reachable?

Linux

sudo ss -ltnup 'sport = :6687'      # process listening on 6687
sudo lsof -nP -i :6687

macOS

sudo lsof -nP -i :6687

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6687 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 6687
netstat -ano | findstr :6687

From another machine

nmap -p 6687 -sV <host>
nc -zv <host> 6687

Block it in the firewall

sudo ufw deny 6687/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 6687" -Direction Inbound -LocalPort 6687 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 6687 used for?

Port 6687 is assigned by IANA to clever-ctrace (CleverView for cTrace Message Service).

Is port 6687 TCP or UDP?

Port 6687 is registered for TCP.

Is it safe to open port 6687?

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 6687 is open?

On Linux run "ss -ltnup 'sport = :6687'", on macOS "lsof -nP -i :6687", and on Windows "netstat -ano | findstr :6687" to see the local process. From another machine, "nmap -p 6687 <host>" shows whether it is reachable.

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