# WHATPORT(61900)

## NAME

port 61900 — Unassigned (dynamic range) — Unregistered and unnamed; the digits resemble 1900 but no UPnP link is documented.

Protocol: TCP  
IANA registry

## DESCRIPTION

61900 has no IANA assignment under RFC 6335's Dynamic/Private range rule. Nmap's nmap-services lists it "unknown" at 0.000304, and SANS ISC shows an empty service field with no CVE links. The tail digits look like UPnP's SSDP port 1900, but nothing in any public source connects the two, so that resemblance is a coincidence unless a capture on your own host proves otherwise. Identify by process, not by pattern.

## EXPOSURE

**Expose with care.** Do not infer a protocol from a suggestive port number. Until the listener is identified, assume nothing about its authentication.

## CHECK

```sh
nc -vz -w 3 TARGET 61900
```

## 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 61900](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=61900) (iana.org)

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HTML: <https://whatport.net/61900/> · JSON: <https://whatport.net/61900.json> · full dataset: <https://whatport.net/ports.json>