# WHATPORT(8889)

## NAME

port 8889 — Jupyter (second instance), HTTP alternate — Where the second Jupyter server lands when 8888 is already taken.

Protocol: TCP  
IANA: ddi-tcp-2

## DESCRIPTION

Jupyter servers try their configured port and then walk upward to the next free one, so a machine already running a notebook on 8888 puts the next on 8889. The same happens with any tool that retries the next port. IANA registers 8889 as ddi-tcp-2 (Desktop Data), which is not something you will encounter. Treat it exactly as you would 8888: identify the process, and assume a notebook until proven otherwise.

## EXPOSURE

**Do not expose.** Same reasoning as 8888 — if this is a notebook server it is arbitrary code execution for anyone who can reach it and get past the token.

## CHECK

```sh
curl -sI http://127.0.0.1:8889/
```

## SEE ALSO

- docs — [Jupyter Notebook docs — running the notebook](https://jupyter-notebook.readthedocs.io/en/stable/notebook.html) (jupyter-notebook.readthedocs.io)
- iana — [IANA Service Name and Transport Protocol Port Number Registry — 8889](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=8889) (iana.org)

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HTML: <https://whatport.net/8889/> · JSON: <https://whatport.net/8889.json> · full dataset: <https://whatport.net/ports.json>