# WHATPORT(5001)

## NAME

port 5001 — commplex-link / Synology DSM HTTPS / iperf 2 — Registered as commplex-link, but in practice Synology DSM over HTTPS or an iperf 2 server.

Protocol: TCP  
IANA registry

## DESCRIPTION

The IANA name for 5001 is commplex-link, a registration with no public protocol behind it, so what you actually meet on this port is a squatter. On a home or small-office network it is usually a Synology NAS: DSM's web interface answers HTTP on 5000 and HTTPS on 5001 by default. On a lab or transit-test host it is more often an iperf 2 server, whose default listen port is 5001 (iperf3 moved to 5201).

## EXPOSURE

**Expose with care.** A DSM login page on the public internet is a brute-force magnet — put it behind a VPN or reverse proxy with MFA. An iperf server accepts traffic from anyone who finds it and should never be left running on a public address.

## CHECK

```sh
curl -sk -o /dev/null -w '%{http_code}\n' https://TARGET:5001/
```

## SEE ALSO

- docs — [Synology Knowledge Center — network ports used by Synology services](https://kb.synology.com/en-us/DSM/tutorial/What_network_ports_are_used_by_Synology_services) (kb.synology.com)
- docs — [iPerf documentation — server port defaults (5001 for iPerf 2)](https://iperf.fr/iperf-doc.php) (iperf.fr)
- iana — [IANA port registry — 5001 (commplex-link)](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=5001) (iana.org)

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HTML: <https://whatport.net/5001/> · JSON: <https://whatport.net/5001.json> · full dataset: <https://whatport.net/ports.json>