Port 8086 InfluxDB · TCP

What runs on port 8086

InfluxDB's HTTP API and UI (v2). Telegraf agents write here; Grafana reads from here. Version 1 had no authentication by default; version 2 requires a token. Either way, keep it on the monitoring network and put TLS on it.

Software that uses it: InfluxDB · Telegraf (writer) · Grafana (reader) · Home Assistant integrations

Should port 8086 be open?

Private network or VPN only. Nothing good comes from this port being reachable from the internet. Keep it on an internal network, reach it over a VPN or an SSH tunnel, and firewall it from everything that does not need it.

• curl -s http://host:8086/health is the liveness check.

Check port 8086

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :8086'
sudo lsof -i :8086

# from another machine: is it reachable?
nc -zv host 8086
nmap -p 8086 host
curl -v telnet://host:8086      # raw TCP connect test, Ctrl-C to leave

A port that answers from the internet when it should not is the finding; nmap from a machine outside your network (or a VPS) is the honest test, because scans from inside the LAN pass the firewall you are trying to verify.

Allow or block port 8086

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 8086 proto tcp
sudo ufw deny 8086/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 8086 accept
nft add rule inet filter input tcp dport 8086 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 8086 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8086 -j DROP

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

Replace 10.0.0.0/8 with the networks that need access. Allowing by source address is the rule that matters; "allow 8086" with no source is just "open".

Related ports

• 9090 Prometheus
• 3000 dev servers — Grafana, Rails, Node apps

Part of the port number reference. Ports are 16-bit numbers; see also the subnet calculator and the packet decoder, which shows ports inside TCP and UDP headers.

Questions