Port 2379 ETCD-CLIENT
Port 2379 is the IANA-assigned etcd-client port for etcd client communication (TCP).
What is port 2379 used for?
Port 2379 is assigned to etcd-client and uses TCP. The IANA registry describes the service as “etcd client communication”. It sits in the registered range, the block used by databases, application servers and developer tooling. Port conflicts here are common when several local services start at once.
Ports are the transport-layer address a service listens on. A client that wants to reach etcd-client connects to port 2379. If nothing is listening, the connection is refused. That is why a port conflict appears whenever two processes try to bind the same number.
Use the commands below to confirm whether port 2379 is actually in use before you change firewall rules. Blocking the port stops new inbound traffic at the firewall, but it does not stop a local process from listening, and it does not remove the service from the machine.
Browse all Containers and orchestration ports
Source: IANA Service Name and Transport Protocol Port Number Registry. Registered assignee: [CoreOS].
Check and block port 2379
Copy-ready commands for the protocols assigned to this port. Run the check first, then block only what should not be reachable.
Check on Linux
sudo ss -tlpn 'sport = :2379'Check on Windows
Get-NetTCPConnection -LocalPort 2379 -State Listen -ErrorAction SilentlyContinueBlock with UFW
sudo ufw deny 2379/tcpBlock with iptables
sudo iptables -A INPUT -p tcp --dport 2379 -j DROPThese commands are examples for a typical host. Check the listener before you change firewall rules, and persist iptables rules with iptables-save or netfilter-persistent. On Windows, use Windows Defender Firewall or New-NetFirewallRule for persistent blocks. The iptables rules here cover IPv4; mirror them with ip6tables if IPv6 is enabled.
Is port 2379 safe to expose?
etcd stores cluster state and secrets. An exposed client endpoint can compromise the whole Kubernetes control plane. Treat this port as sensitive. Restrict it to trusted networks or a VPN, require authentication and logging, and never expose it directly to the public internet without a hardened gateway in front.
Where port 2379 is usually used
Most traffic on port 2379 falls into these scenarios. The demo below is a safe way to confirm the listener before you change anything.
- Cluster control-plane traffic and automation clients managing workloads.
- Operators inspecting nodes, pods and secrets from a trusted network.
- CI pipelines deploying manifests against a cluster endpoint.
Check etcd health
This queries the etcd client endpoint; peer port 2380 uses a different protocol and should stay internal.
ETCDCTL_API=3 etcdctl --endpoints=http://127.0.0.1:2379 endpoint healthCommon problems with port 2379
Connection refused or timed out
Refused usually means the host is reachable but nothing is listening on port 2379. A timeout more often means a firewall drop, a wrong host or a service bound to a different interface.
Port already in use
Find the process holding the port with sudo ss -tlpn 'sport = :2379' or sudo lsof -i :2379. Stop that process or configure it to bind another port; killing it without identifying it can take down a production service.
Firewall rule did not survive a reboot
UFW and Windows Firewall keep rules across restarts. Raw iptables rules do not: save them with iptables-save or the netfilter-persistent package, and re-apply after upgrades that reset the ruleset.
The port is blocked but still reachable
A firewall rule filters inbound traffic; it does not close the listener. Confirm with the check command above and bind the service to 127.0.0.1 when only local clients need it.
Port 2379 at a glance
| Port number | 2379 |
|---|---|
| Service name | etcd-client |
| Transport protocol | TCP |
| Category | Containers and orchestration |
| Range | Registered port (1024–10000) |
| Risk level | High |
| Registered assignee | [CoreOS] |
| Registry description | etcd client communication |
| Source | IANA Service Name and Transport Protocol Port Number Registry |
Frequently asked questions
What is port 2379 used for?
Port 2379 (ETCD-CLIENT) uses TCP. etcd client communication.
How do I check if port 2379 is open?
On Linux run `sudo ss -tlpn 'sport = :2379'`. On Windows run `Get-NetTCPConnection -LocalPort 2379 -State Listen -ErrorAction SilentlyContinue` in PowerShell. If the port is open, the output shows a process listening on port 2379; empty output usually means nothing is bound to it.
How do I block port 2379?
With UFW run `sudo ufw deny 2379/tcp`. With iptables run `sudo iptables -A INPUT -p tcp --dport 2379 -j DROP`. Persist the iptables rules with your distribution's netfilter-persistent or iptables-save tooling so they survive a reboot.
Is port 2379 safe to expose?
etcd stores cluster state and secrets. An exposed client endpoint can compromise the whole Kubernetes control plane. Nevertheless, treat this port as sensitive. Restrict it to trusted networks or a VPN, require authentication and logging, and never expose it directly to the public internet without a hardened gateway in front.
Related ports
- Port 2377 · swarmRPC interface for Docker Swarm
- Port 2380 · etcd-serveretcd server to server communication
- Port 2376 · docker-sDocker REST API (ssl)
- Port 4665 · contclientmsContainer Client Message Service
- Port 2375 · dockerDocker REST API (plain text)
- Port 5638 · flcrsSymantec Fingerprint Lookup and Container Reference Service
Primary data: IANA Service Name and Transport Protocol Port Number Registry.
Last reviewed 2026-10-30 · Methodology · About · Privacy