# WHATPORT(63331)

## NAME

port 63331 — Unassigned (dynamic range) — No registration, no named service, and more UDP sightings than TCP in Nmap's data.

Protocol: TCP  
IANA registry

## DESCRIPTION

63331 falls in the range RFC 6335 reserves for dynamic and private use, so IANA has nothing on it. Nmap's nmap-services carries TCP at 0.000380 and UDP at 0.001004, both "unknown", which is why the port appears in a default scan. SANS ISC has an empty service field; the only attribution there is an unsourced visitor comment naming a long-discontinued Microsoft product, which is not verifiable and is not repeated here. What is verifiable is that it is unregistered and unidentified.

## EXPOSURE

**Expose with care.** An unidentified listener has unknown authentication and unknown encryption. Keep it internal until you know what it is.

## CHECK

```sh
nmap -Pn -sV --version-all -p 63331 TARGET
```

## SEE ALSO

- spec — [RFC 6335 — Dynamic Ports (49152-65535)](https://www.rfc-editor.org/rfc/rfc6335.html) (rfc-editor.org)
- iana — [IANA port registry — search 63331](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=63331) (iana.org)
- source — [nmap/nmap — nmap-services frequency data](https://github.com/nmap/nmap/blob/master/nmap-services) (github.com)

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HTML: <https://whatport.net/63331/> · JSON: <https://whatport.net/63331.json> · full dataset: <https://whatport.net/ports.json>