# WHATPORT(9877)

## NAME

port 9877 — x510 — X.510 wrapper protocol — The ITU-T X.510 wrapper protocol for secure directory operations — registered in 2019, seldom seen outside PKI and directory products.

Protocol: TCP  
IANA registry

## DESCRIPTION

IANA registered 9877/tcp as `x510` in 2019 on behalf of ITU-T Study Group 17, referencing ITU-T X.510 / ISO/IEC 9584-11, "Protocol specifications for secure operations" in the OSI Directory series. The wrapper protocol carries authenticated and integrity-protected directory operations, and shows up in X.500-lineage directory and PKI implementations rather than general infrastructure. UDP 9877 is Reserved. On a typical network this port is empty.

## EXPOSURE

**Expose with care.** The protocol is designed with its own authentication and integrity protection, but a directory service is still directory data. Expose it only if you have deliberately deployed X.510 and configured its trust anchors.

## CHECK

```sh
nc -vz TARGET 9877
```

## SEE ALSO

- spec — [ITU-T Recommendation X.510 — Protocol specifications for secure operations](https://www.itu.int/rec/T-REC-X.510/en) (itu.int)
- iana — [IANA Service Name and Transport Protocol Port Number Registry](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml) (iana.org)

---

HTML: <https://whatport.net/9877/> · JSON: <https://whatport.net/9877.json> · full dataset: <https://whatport.net/ports.json>