# WHATPORT(911)

## NAME

port 911 — xact-backup — Registered decades ago for a backup product, with no public protocol and essentially no sightings.

Protocol: TCP  
IANA: xact-backup

## DESCRIPTION

IANA lists 911/tcp and 911/udp as xact-backup, assigned to an individual, with no description beyond the name and no specification anywhere. Nothing in common use implements it. nmap's frequency data ranks 911 among the rarest ports to find open at all. If something is listening, a person chose the number — the memorable one, most likely — and the registry will tell you nothing useful about it; the banner will.

## EXPOSURE

**Expose with care.** There is no standard service to reason about, so this is an unidentified listener. Find out what it is before leaving it reachable from anywhere.

## CHECK

```sh
sudo lsof -nP -iTCP:911 -sTCP:LISTEN
```

## SEE ALSO

- iana — [IANA port registry — 911](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=911) (iana.org)
- source — [nmap-services (911/tcp xact-backup)](https://github.com/nmap/nmap/blob/master/nmap-services) (github.com)

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HTML: <https://whatport.net/911/> · JSON: <https://whatport.net/911.json> · full dataset: <https://whatport.net/ports.json>