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Port 4318 (OpenTelemetry OTLP HTTP)

OTLP over HTTP/protobuf or JSON to the OpenTelemetry Collector.

Registered (user) port, 1024-49151 TCP Monitoring and logging Do not expose to the internet

What port 4318 is used for

OTLP over HTTP/protobuf or JSON to the OpenTelemetry Collector.

Security: should port 4318 be open?

Do not expose to the internet. Same as 4317.

IANA assignment

Port 4318 is in the registered range and has no IANA assignment. The usage above is unofficial but widespread.

Check what is listening on port 4318

Linux: is anything listening on TCP 4318?
sudo ss -tlnp 'sport = :4318'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4318
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4318 '
Windows (Command Prompt)
netstat -ano | findstr :4318
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4318 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4318
From Windows
Test-NetConnection HOST -Port 4318

Block port 4318 in the firewall

ufw
sudo ufw deny 4318/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4318 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4318 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4318' -Direction Inbound -Protocol TCP -LocalPort 4318 -Action Block

Related ports

4317OpenTelemetry OTLP gRPC16686Jaeger UI4316choiceview-clt4319skytale4320fdt-rcatp4321rwhois

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.