Port 8086: InfluxDB

What uses port 8086

InfluxDB, a time-series database for metrics and IoT data, serves its HTTP API and (in 2.x) web UI on 8086. Telegraf agents write metrics to it, and Grafana reads from it. InfluxDB 3 Core listens on 8181 by default.

Should port 8086 be open to the internet?

Keep private. Never expose this port to the internet. Keep it on localhost, a private network or behind a VPN or SSH tunnel.

Check what is listening on port 8086

sudo ss -ltnp 'sport = :8086'

sudo lsof -nP -iTCP:8086 -sTCP:LISTEN

Get-NetTCPConnection -LocalPort 8086 -State Listen
netstat -ano | findstr :8086

No output means nothing is listening. If a service should be, check that it is running and which address it binds to: 127.0.0.1 only accepts local connections, 0.0.0.0 or :: accepts them on every interface.

Fix “address already in use” on port 8086

Another process already holds the port. Find it with the commands above, then stop that service properly, or end the process:

sudo kill $(sudo lsof -t -iTCP:8086 -sTCP:LISTEN)

Stop-Process -Id (Get-NetTCPConnection -LocalPort 8086 -State Listen).OwningProcess

Allow port 8086 from trusted networks only

The examples allow 8086 only from 10.0.0.0/8; replace it with your own private network, office IP or VPN range.

sudo ufw allow from 10.0.0.0/8 to any port 8086 proto tcp
# Close it again:
sudo ufw delete allow from 10.0.0.0/8 to any port 8086 proto tcp

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="10.0.0.0/8" port port="8086" protocol="tcp" accept'
sudo firewall-cmd --reload

New-NetFirewallRule -DisplayName "InfluxDB 8086/TCP" -Direction Inbound -Protocol TCP -LocalPort 8086 -Action Allow -RemoteAddress 10.0.0.0/8

On AWS, Google Cloud and Azure, also allow the port in the security group or network firewall rules; host firewalls and cloud firewalls are separate.

Port 8086 with Docker

# Publish on localhost only. Docker's port rules bypass ufw and firewalld,
# so -p 8086:8086 would expose the port to the whole network.
docker run -d -p 127.0.0.1:8086:8086 influxdb

The format is -p host_port:container_port. Containers on the same Docker network reach each other on the container port directly, without publishing it. Convert a long docker run command into a Compose file with docker run to compose.

Test port 8086 from another machine

nc -zv example.com 8086

Test-NetConnection example.com -Port 8086

Related ports

• Port 3000 (Development server / Grafana): the default port of many development servers and of Grafana.
• Port 9090 (Prometheus): the default port of the Prometheus server.

More databases ports

1433 (Microsoft SQL Server) , 1434 (SQL Server Browser) , 1521 (Oracle Database) , 3306 (MySQL / MariaDB) , 5432 (PostgreSQL) , 6379 (Redis) , 9042 (Cassandra / ScyllaDB) , 9200 (Elasticsearch / OpenSearch) . See all ports in the port lookup.

Sources

• IANA port registry (not registered for this use)

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Frequently asked questions