# WHATPORT(18040)

## NAME

port 18040 — Unassigned — No IANA registration and no documented default — an unidentified high port that scanners probe by habit.

Protocol: TCP  
IANA registry

## DESCRIPTION

18040 is unassigned in the IANA registry and unnamed in Nmap's services database, but it is inside Nmap's default top-1000 TCP set because of observed open-port frequency. The registered ports nearby (18000 biimenu, 18104 radpdf) have no relationship to it. Whatever listens on 18040 chose the number itself.

## EXPOSURE

**Expose with care.** Identify the process first. An unknown listener reachable from the internet is worth closing until someone can name it.

## CHECK

```sh
sudo lsof -nP -iTCP:18040 -sTCP:LISTEN
```

## SEE ALSO

- 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)
- source — [Nmap services frequency database](https://github.com/nmap/nmap/blob/master/nmap-services) (github.com)

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HTML: <https://whatport.net/18040/> · JSON: <https://whatport.net/18040.json> · full dataset: <https://whatport.net/ports.json>