# WHATPORT(1334)

## NAME

port 1334 — AIX writesrv — AIX's writesrv daemon — accepts remote `write` messages to users' terminals.

Protocol: TCP  
IANA registry

## DESCRIPTION

On IBM AIX, writesrv listens on the port named in /etc/services (1334) and handles incoming requests from the `write` command, spawning a server process per request so a user on one host can write messages to a logged-in user's terminal on another. Both hosts must be running the daemon for remote `write` to work. It is an old inetd-era convenience service that AIX hardening guides tell you to disable, and it is the only well-documented user of this port.

## EXPOSURE

**Do not expose.** IBM's own guidance is to disable writesrv on any system connected to a public network; it accepts unauthenticated terminal messages and offers nothing worth the risk.

## CHECK

```sh
lssrc -s writesrv
```

## SEE ALSO

- docs — [IBM AIX documentation — writesrv daemon](https://www.ibm.com/docs/ssw_aix_72/w_commands/writesrv.html) (ibm.com)
- 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)

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