# WHATPORT(2043)

## NAME

port 2043 — isis-bcast (registration only) — The companion registration to 2042's "isis", equally undocumented.

Protocol: TCP/UDP  
IANA registry

## DESCRIPTION

IANA lists isis-bcast on TCP and UDP 2043, assigned to Ken Chapman, with the service name repeated as its only description and no reference document. It pairs with isis on 2042 and, like it, has nothing to do with the IS-IS routing protocol, which runs over layer 2 and uses no transport port. Nmap sees 2043 open on roughly 0.02% of hosts, so in practice this is a name in a table rather than a protocol you will meet.

## EXPOSURE

**Expose with care.** No documented protocol means no defensible default. Identify the process behind an open 2043 before deciding anything about exposure.

## CHECK

```sh
sudo lsof -nP -iTCP:2043 -sTCP:LISTEN
```

## SEE ALSO

- 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)
- source — [nmap-services — Nmap port frequency data](https://github.com/nmap/nmap/blob/master/nmap-services) (github.com)

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HTML: <https://whatport.net/2043/> · JSON: <https://whatport.net/2043.json> · full dataset: <https://whatport.net/ports.json>