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// DevOps, cloud & containers

Port 4665: Container Client Message Service

Port 4665 is assigned by IANA to contclientms (Container Client Message Service).

4665

How contclientms works

DevOps, cloud & containers
adminhostcontclientms adminhostcontclientms

Commands sent to port 4665 create and control containers or cluster resources on the host.

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
DevOps, cloud & containers
01 Security

Is port 4665 dangerous?

We have no specific security note for port 4665. Its risk depends on the program actually listening on it. General advice for devops, cloud & containers services:

  • Container and orchestration APIs give full control of hosts: require mutual TLS and RBAC.
  • Never expose them to the Internet.
  • Rotate tokens and certificates and audit who has access.
02 Registry

IANA registry entries for port 4665

ServicePortTransportDescriptionReferenceUpdated
contclientms 4665 TCP, UDP Container Client Message Service - 2006-02

// source: IANA service name and port number registry

03 Check it

Which program uses port 4665, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4665'      # process listening on 4665
sudo lsof -nP -i :4665

macOS

sudo lsof -nP -i :4665

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4665 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4665
netstat -ano | findstr :4665

From another machine

nmap -p 4665 -sV <host>
sudo nmap -sU -p 4665 <host>
nc -zv <host> 4665

Block it in the firewall

sudo ufw deny 4665/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4665" -Direction Inbound -LocalPort 4665 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4665 used for?

Port 4665 is assigned by IANA to contclientms (Container Client Message Service).

Is port 4665 TCP or UDP?

Port 4665 is registered for TCP and UDP.

Is it safe to open port 4665?

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. Container and orchestration APIs give full control of hosts: require mutual TLS and RBAC.

How do I check if port 4665 is open?

On Linux run "ss -ltnup 'sport = :4665'", on macOS "lsof -nP -i :4665", and on Windows "netstat -ano | findstr :4665" to see the local process. From another machine, "nmap -p 4665 <host>" shows whether it is reachable.

05 Related
:2375 Docker API (HTTP) tcp · critical risk :2376 Docker API (TLS) tcp · high risk :6443 Kubernetes API tcp · udp · high risk :10250 Kubelet API tcp · critical risk :2379 etcd tcp · critical risk :8500 Consul tcp · udp · high risk :4505 SaltStack tcp · critical risk :9000 PHP-FPM / SonarQube / Portainer tcp · udp · high risk

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