Port 19999 NETDATA
Port 19999 is most commonly used by Netdata. The IANA registry lists TCP / UDP / SCTP for this number.
What is port 19999 used for?
Port 19999 is most commonly used by Netdata. Netdata's web dashboard commonly listens on port 19999; the IANA registry assigns the number to dnp-sec. It sits above the registered range, where most numbers are transient client ports. A fixed high port is worth documenting precisely because tooling often assumes the default.
Ports are the transport-layer address a service listens on. A client that wants to reach dnp-sec connects to port 19999. A TCP connection is refused when nothing is listening, while a UDP request simply goes unanswered. That is why a port conflict appears whenever two processes try to bind the same number.
Use the commands below to confirm whether port 19999 is actually in use before you change firewall rules. Blocking the port stops new inbound traffic at the firewall, but it does not stop a local process from listening, and it does not remove the service from the machine.
Browse all Monitoring and metrics ports
Source: IANA Service Name and Transport Protocol Port Number Registry. Registered assignee: [DNP_Users_Group].
Check and block port 19999
Copy-ready commands for the protocols assigned to this port. Run the check first, then block only what should not be reachable.
Check on Linux
sudo ss -tlpn 'sport = :19999'
sudo ss -ulpn 'sport = :19999'
sudo ss -Slpn 'sport = :19999'Check on Windows
Get-NetTCPConnection -LocalPort 19999 -State Listen -ErrorAction SilentlyContinue
Get-NetUDPEndpoint -LocalPort 19999 -ErrorAction SilentlyContinueBlock with UFW
sudo ufw deny 19999/tcp
sudo ufw deny 19999/udpBlock with iptables
sudo iptables -A INPUT -p tcp --dport 19999 -j DROP
sudo iptables -A INPUT -p udp --dport 19999 -j DROP
sudo iptables -A INPUT -p sctp --dport 19999 -j DROPThese commands are examples for a typical host. Check the listener before you change firewall rules, and persist iptables rules with iptables-save or netfilter-persistent. On Windows, use Windows Defender Firewall or New-NetFirewallRule for persistent blocks. The iptables rules here cover IPv4; mirror them with ip6tables if IPv6 is enabled. UFW and the built-in Windows cmdlets cover TCP and UDP only; this port also lists SCTP, so use nftables, iptables or the vendor's diagnostic tool for those protocols. SCTP and DCCP handling also depends on kernel support, including their diagnostic modules, so a missing result may mean the module is not loaded rather than that nothing is listening.
Is port 19999 safe to expose?
Netdata's dashboard can expose detailed host metrics without authentication. Put it behind a reverse proxy or restrict it to trusted networks. Expose this port only when the service is actually needed. Keep it patched, prefer an encrypted alternative, and limit source addresses with a firewall allowlist.
Where port 19999 is usually used
Most traffic on port 19999 falls into these scenarios. The demo below is a safe way to confirm the listener before you change anything.
- Scrapers such as Prometheus pulling metrics from port 19999 on a schedule.
- Dashboards and alerting rules querying the same endpoint.
- Incident reviews comparing metrics before and after a deployment.
Read the Netdata info
The API returns host and agent information as JSON.
curl -s http://127.0.0.1:19999/api/v1/infoCommon problems with port 19999
Connection refused or timed out
Refused usually means the host is reachable but nothing is listening on port 19999. A timeout more often means a firewall drop, a wrong host or a service bound to a different interface.
Port already in use
Find the process holding the port with sudo ss -tlpn 'sport = :19999' or sudo lsof -i :19999. Stop that process or configure it to bind another port; killing it without identifying it can take down a production service.
Firewall rule did not survive a reboot
UFW and Windows Firewall keep rules across restarts. Raw iptables rules do not: save them with iptables-save or the netfilter-persistent package, and re-apply after upgrades that reset the ruleset.
The port is blocked but still reachable
A firewall rule filters inbound traffic; it does not close the listener. Confirm with the check command above and bind the service to 127.0.0.1 when only local clients need it.
Port 19999 at a glance
| Port number | 19999 |
|---|---|
| IANA service name | dnp-sec |
| Commonly used by | Netdata |
| Transport protocol | TCP / UDP / SCTP |
| Category | Monitoring and metrics |
| Range | High port (10001–65535) |
| Risk level | Medium |
| Registered assignee | [DNP_Users_Group] |
| Registry description | Distributed Network Protocol - secured |
| Source | IANA Service Name and Transport Protocol Port Number Registry |
Frequently asked questions
What is port 19999 used for?
Port 19999 (NETDATA). The IANA registry lists TCP / UDP / SCTP for this number. Netdata's web dashboard commonly listens on port 19999; the IANA registry assigns the number to dnp-sec.
How do I check if port 19999 is open?
On Linux run `sudo ss -tlpn 'sport = :19999'` and `sudo ss -ulpn 'sport = :19999'` and `sudo ss -Slpn 'sport = :19999'`. On Windows run `Get-NetTCPConnection -LocalPort 19999 -State Listen -ErrorAction SilentlyContinue` and `Get-NetUDPEndpoint -LocalPort 19999 -ErrorAction SilentlyContinue` in PowerShell. If the port is open, the output shows a process listening on port 19999; empty output usually means nothing is bound to it. UFW and the built-in Windows cmdlets cover TCP and UDP only; SCTP needs nftables, iptables or the vendor's diagnostic tool.
How do I block port 19999?
With UFW run `sudo ufw deny 19999/tcp` and `sudo ufw deny 19999/udp`. With iptables run `sudo iptables -A INPUT -p tcp --dport 19999 -j DROP` and `sudo iptables -A INPUT -p udp --dport 19999 -j DROP` and `sudo iptables -A INPUT -p sctp --dport 19999 -j DROP`. Persist the iptables rules with your distribution's netfilter-persistent or iptables-save tooling so they survive a reboot. UFW covers TCP and UDP only; use iptables or nftables for SCTP.
Is port 19999 safe to expose?
Netdata's dashboard can expose detailed host metrics without authentication. Put it behind a reverse proxy or restrict it to trusted networks. Nevertheless, expose this port only when the service is actually needed. Keep it patched, prefer an encrypted alternative, and limit source addresses with a firewall allowlist.
Related ports
- Port 19998 · iec-104-secIEC 60870-5-104 process control - secure
- Port 20000 · dnpDistributed Network Protocol
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- Port 15692 · RabbitMQ exporterPrometheus metrics endpoint exposed by the RabbitMQ exporter…
- Port 45001 · asmpsNuance AutoStore Status Monitoring Protocol (secure data transfer)
Primary data: IANA Service Name and Transport Protocol Port Number Registry.
Last reviewed 2026-10-30 · Methodology · About · Privacy