# WHATPORT(9091)

## NAME

port 9091 — Transmission RPC / Prometheus Pushgateway — Usually a Transmission BitTorrent web UI or a Prometheus Pushgateway — both default here.

Protocol: TCP  
IANA registry

## DESCRIPTION

IANA has 9091 registered to a private assignment called xmltec-xmlmail that you will essentially never meet. In practice the port belongs to two popular pieces of software: Transmission's RPC and web interface (the /transmission/web/ UI behind transmission-daemon), and the Prometheus Pushgateway, which listens on 9091 by default for metrics pushed by batch jobs. On a home or lab network a listener here is almost always Transmission on a NAS or seedbox; in a monitoring stack it is the Pushgateway.

## EXPOSURE

**Do not expose.** Transmission's RPC lets a caller add torrents and set the download directory, and older builds shipped with weak or absent authentication; the Pushgateway accepts unauthenticated metric writes and deletes. Keep both on the LAN or behind an authenticating reverse proxy.

## CHECK

```sh
curl -sS -m 5 -o /dev/null -w '%{http_code}\n' http://TARGET:9091/
```

## SEE ALSO

- source — [transmission/transmission](https://github.com/transmission/transmission) (github.com)
- source — [prometheus/pushgateway (default listen port 9091)](https://github.com/prometheus/pushgateway) (github.com)
- iana — [IANA port registry — 9091 (xmltec-xmlmail)](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=9091) (iana.org)

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