Port 8000 dev servers · TCP

What runs on port 8000

Django's runserver, python -m http.server, PHP's built-in server in many tutorials, and plenty of other development servers. Also the port of some real products (Splunk's web UI, Portainer in some installs). Like 3000 and 5000, it should not be reachable from outside a workstation; development servers are single-threaded and have no security hardening.

Software that uses it: Django (runserver) · python -m http.server · Splunk Web · various dev servers

Should port 8000 be open?

Loopback or the host's own network only. The service should listen on 127.0.0.1 (or a Unix socket) and be reached by a reverse proxy or by the application on the same host. If it answers on a public address, that is a misconfiguration.

• python -m http.server binds to all interfaces by default; add --bind 127.0.0.1 when sharing a file on a laptop in a café.

Check port 8000

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :8000'
sudo lsof -i :8000

# from another machine: is it reachable?
nc -zv host 8000
nmap -p 8000 host
curl -v telnet://host:8000      # 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 8000

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 8000 proto tcp
sudo ufw deny 8000/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 8000 accept
nft add rule inet filter input tcp dport 8000 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 8000 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8000 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=8000 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 8000" with no source is just "open".

Putting it behind nginx

server {
    listen 443 ssl;
    server_name app.example.com;
    location / {
        proxy_pass http://127.0.0.1:8000;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto https;
    }
}

Then make the application listen on 127.0.0.1:8000 only. Test which location block a request hits with the nginx location tester.

Related ports

• 8080 HTTP alt — Tomcat, proxies, dev servers
• 3000 dev servers — Grafana, Rails, Node apps
• 5000 dev servers — Flask, Docker registry, UPnP
• 8008 HTTP alt

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