# WHATPORT(19)

## NAME

port 19 — CHARGEN (Character Generator) — CHARGEN — an endless stream of printable characters, and a classic DDoS amplification source.

Protocol: TCP/UDP  
IANA registry

## DESCRIPTION

RFC 864 defines CHARGEN as a test service: over TCP it sends an unending pattern of ASCII characters until the client disconnects, and over UDP it answers each datagram with a random-length payload of up to 512 characters. It was written to exercise packet generation and printer paths, and shipped as an inetd built-in and a Windows Simple TCP/IP Services component. It is disabled by default on modern systems. Its UDP form is one of the most abused reflectors on the internet because a tiny spoofed request produces a much larger reply aimed at the victim.

## EXPOSURE

**Do not expose.** A documented high-ratio UDP amplification vector in CISA's alert; an internet-reachable CHARGEN server is a weapon pointed at third parties.

## CHECK

```sh
nc -v TARGET 19 | head -c 200
```

## SEE ALSO

- spec — [RFC 864 — Character Generator Protocol](https://www.rfc-editor.org/rfc/rfc864.html) (rfc-editor.org)
- docs — [CISA Alert — UDP-Based Amplification Attacks](https://www.cisa.gov/news-events/alerts/2014/01/17/udp-based-amplification-attacks) (cisa.gov)
- iana — [IANA Service Name and Transport Protocol Port Number Registry](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml) (iana.org)

---

HTML: <https://whatport.net/19/> · JSON: <https://whatport.net/19.json> · full dataset: <https://whatport.net/ports.json>