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Local dataset, no network
// DevOps, cloud & containers

Port 2138: UNBIND-CLUSTER

Port 2138 is assigned by IANA to unbind-cluster (UNBIND-CLUSTER).

2138

How unbind-cluster works

DevOps, cloud & containers
adminhostunbind-cluster adminhostunbind-cluster

Commands sent to port 2138 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 2138 dangerous?

We have no specific security note for port 2138. 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 2138

ServicePortTransportDescriptionReferenceUpdated
unbind-cluster 2138 TCP, UDP UNBIND-CLUSTER - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2138, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2138'      # process listening on 2138
sudo lsof -nP -i :2138

macOS

sudo lsof -nP -i :2138

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2138 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2138
netstat -ano | findstr :2138

From another machine

nmap -p 2138 -sV <host>
sudo nmap -sU -p 2138 <host>
nc -zv <host> 2138

Block it in the firewall

sudo ufw deny 2138/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2138" -Direction Inbound -LocalPort 2138 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2138 used for?

Port 2138 is assigned by IANA to unbind-cluster (UNBIND-CLUSTER).

Is port 2138 TCP or UDP?

Port 2138 is registered for TCP and UDP.

Is it safe to open port 2138?

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 2138 is open?

On Linux run "ss -ltnup 'sport = :2138'", on macOS "lsof -nP -i :2138", and on Windows "netstat -ano | findstr :2138" to see the local process. From another machine, "nmap -p 2138 <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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