PortAtlas.
Registered port (1024–10000) Standard/Low risk Community convention

Port 4318 OPENTELEMETRY OTLP HTTP

Quick answer

Port 4318 is the community default for OpenTelemetry OTLP HTTP, using TCP.

Check and block Is it safe? Troubleshooting FAQ
TransportTCP
RiskStandard/Low
Typical useWeb and HTTP

What is port 4318 used for?

Port 4318 is widely used by OpenTelemetry OTLP HTTP (TCP), a community convention rather than an IANA assignment. OpenTelemetry Protocol (OTLP) HTTP receiver port (community convention; not IANA-assigned). 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 OpenTelemetry OTLP HTTP connects to port 4318. 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 4318 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.

Because this number is not IANA-assigned, a different application may legitimately use it on a machine you do not control. Always identify the actual listening process before deciding that the port belongs to this technology.

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This port number is not assigned by IANA. The entry documents a widely adopted community convention.

Check and block port 4318

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 = :4318'

Check on Windows

Get-NetTCPConnection -LocalPort 4318 -State Listen -ErrorAction SilentlyContinue

Block with UFW

sudo ufw deny 4318/tcp

Block with iptables

sudo iptables -A INPUT -p tcp --dport 4318 -j DROP

These 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 4318 safe to expose?

Standard/Low

This port is not on our curated list of services with a widely exploited profile. Exposure is only safe when the listening service is intended, patched and protected by a firewall. Keep the listening service patched and remove it if unused. A default-deny firewall policy with explicit allow rules is still the safest baseline.

Where port 4318 is usually used

Most traffic on port 4318 falls into these scenarios. The demo below is a safe way to confirm the listener before you change anything.

Demo

Send a test request

Start a local web server, then ask the port for response headers. Replace 127.0.0.1 with the host you are testing.

curl -I http://127.0.0.1:4318

Common problems with port 4318

Connection refused or timed out

Refused usually means the host is reachable but nothing is listening on port 4318. 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 = :4318' or sudo lsof -i :4318. 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 4318 at a glance

Port number4318
Service nameOpenTelemetry OTLP HTTP
Transport protocolTCP
CategoryWeb and HTTP
RangeRegistered port (1024–10000)
Risk levelStandard/Low
ReferenceCommunity convention (not IANA-assigned)
Registry descriptionOpenTelemetry Protocol (OTLP) HTTP receiver port (community convention; not IANA-assigned)
SourceCommunity convention

Frequently asked questions

What is port 4318 used for?

Port 4318 (OPENTELEMETRY OTLP HTTP) uses TCP. OpenTelemetry Protocol (OTLP) HTTP receiver port (community convention; not IANA-assigned) (community convention, not an IANA assignment).

How do I check if port 4318 is open?

On Linux run `sudo ss -tlpn 'sport = :4318'`. On Windows run `Get-NetTCPConnection -LocalPort 4318 -State Listen -ErrorAction SilentlyContinue` in PowerShell. If the port is open, the output shows a process listening on port 4318; empty output usually means nothing is bound to it.

How do I block port 4318?

With UFW run `sudo ufw deny 4318/tcp`. With iptables run `sudo iptables -A INPUT -p tcp --dport 4318 -j DROP`. Persist the iptables rules with your distribution's netfilter-persistent or iptables-save tooling so they survive a reboot.

Is port 4318 safe to expose?

This port is not on our curated list of services with a widely exploited profile. Exposure is only safe when the listening service is intended, patched and protected by a firewall. Nevertheless, keep the listening service patched and remove it if unused. A default-deny firewall policy with explicit allow rules is still the safest baseline.

See all Web and HTTP ports

Primary data: IANA Service Name and Transport Protocol Port Number Registry. This number is a community convention, not an IANA assignment.

Last reviewed 2026-10-30 · Methodology · About · Privacy