Port 8008 HTTP alt · TCP

What runs on port 8008

An alternative HTTP port, registered as "http-alt" alongside 8080. Used by Chromecast and Google Home devices for their local API, by some Matrix (Synapse) deployments for client traffic, and by IBM HTTP Server by default.

Software that uses it: Chromecast / Google Cast devices · Synapse (Matrix) · IBM HTTP Server

Should port 8008 be open?

Internet-facing only with authentication and care. It can be exposed when the service behind it is authenticated, rate-limited and kept up to date; most deployments are better off behind a VPN, an allow-list or a reverse proxy.

• Synapse behind a reverse proxy should listen on 8008 on localhost only, with the proxy on 443 and 8448 for federation.

Check port 8008

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :8008'
sudo lsof -i :8008

# from another machine: is it reachable?
nc -zv host 8008
nmap -p 8008 host
curl -v telnet://host:8008      # 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 8008

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 8008 proto tcp
sudo ufw deny 8008/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 8008 accept
nft add rule inet filter input tcp dport 8008 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 8008 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8008 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=8008 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 8008" with no source is just "open".

Putting it behind nginx

server {
    listen 443 ssl;
    server_name app.example.com;
    location / {
        proxy_pass http://127.0.0.1:8008;
        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 127.0.0.1:8008 only. Test which location block a request hits with the nginx location tester.

Related ports

• 8080 HTTP alt — Tomcat, proxies, dev servers
• 80 HTTP — Web, unencrypted
• 8448 Matrix federation

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