Port 10000 Webmin · TCP

What runs on port 10000

Webmin, the web-based system administration panel, listens here over HTTPS by default. Also the start of the default RTP media range in Asterisk (10000–20000 UDP) and the Network Data Management Protocol (NDMP) for backups. Webmin runs as root and has had remote code execution bugs; keep it behind a VPN or an IP allow-list.

Software that uses it: Webmin / Virtualmin · Asterisk RTP range (UDP) · NDMP (backup appliances) · Cisco, Veeam, Synology use 10000 for various things

Should port 10000 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.

• Webmin: /etc/webmin/miniserv.conf "allow=" limits source addresses; its 2FA option is worth enabling.

Check port 10000

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :10000'
sudo lsof -i :10000

# from another machine: is it reachable?
nc -zv host 10000
nmap -p 10000 host
curl -v telnet://host:10000      # 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 10000

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 10000 proto tcp
sudo ufw deny 10000/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 10000 accept
nft add rule inet filter input tcp dport 10000 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 10000 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 10000 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=10000 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 10000" with no source is just "open".

Putting it behind nginx

server {
    listen 443 ssl;
    server_name app.example.com;
    location / {
        proxy_pass http://127.0.0.1:10000;
        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 127.0.0.1:10000 only. Test which location block a request hits with the nginx location tester.

Related ports

• 5060 SIP — VoIP signalling
• 8443 HTTPS alt — Tomcat, Plesk, Unifi
• 20000 RTP range end / Usermin — Asterisk 10000–20000

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