# WHATPORT(1687)

## NAME

port 1687 — nsjtp-ctrl — The control channel of Netscape's Java Transaction Protocol — a dead product's registration.

Protocol: TCP  
IANA registry

## DESCRIPTION

IANA registers 1687 as "nsjtp-ctrl" (TCP and UDP), the control half of Netscape's JTP, paired with "nsjtp-data" on 1688. It belonged to Netscape's application-server line, which passed through iPlanet and Sun and no longer exists. There is no current implementation and no public specification, so the registration is historical only.

## EXPOSURE

**Expose with care.** Nothing in current use binds 1687, so an open port here is an unidentified listener that needs to be traced to a process before you judge it.

## CHECK

```sh
nc -vz -w 3 TARGET 1687
```

## SEE ALSO

- iana — [IANA port registry — 1687](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=1687) (iana.org)

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HTML: <https://whatport.net/1687/> · JSON: <https://whatport.net/1687.json> · full dataset: <https://whatport.net/ports.json>