# WHATPORT(3517)

## NAME

port 3517 — 802-11-iapp (IEEE 802.11 IAPP) — Inter-Access Point Protocol, from a withdrawn IEEE trial-use standard for AP-to-AP roaming handoff.

Protocol: TCP/UDP  
IANA registry

## DESCRIPTION

IANA registered 3517 in 2002 for the IEEE 802.11 working group's Inter-Access Point Protocol, the mechanism by which access points on the same subnet told each other that a station had roamed and handed over its context. It was published as IEEE 802.11F, a trial-use standard, and withdrawn in 2006; vendors moved to controller-based architectures and CAPWAP instead. If you see it, you are looking at an old autonomous access point on a management VLAN, not at anything current.

## EXPOSURE

**Do not expose.** This is wireless infrastructure signalling between APs on a trusted segment, with no authentication worth the name — it has no business crossing a routed boundary, let alone reaching the internet.

## CHECK

```sh
nmap -Pn -sU -sT -p 3517 TARGET
```

## SEE ALSO

- iana — [IANA port registry — 3517 (802-11-iapp)](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=3517) (iana.org)

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HTML: <https://whatport.net/3517/> · JSON: <https://whatport.net/3517.json> · full dataset: <https://whatport.net/ports.json>