---
name: "zmq_plain"
section: "7"
platform: "linux"
package: "zeromq"
version: "4.3.5-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/zmq_plain"
---

# zmq\_plain(7)

clear-text authentication

## NAME

zmq\_plain - clear-text authentication

## SYNOPSIS

The PLAIN mechanism defines a simple username/password mechanism that lets a server authenticate a client. PLAIN makes no attempt at security or confidentiality. It is intended for use on internal networks where security requirements are low. The PLAIN mechanism is defined by this document: **http://rfc.zeromq.org/spec:24**.

## USAGE

To use PLAIN, the server shall set the ZMQ\_PLAIN\_SERVER option, and the client shall set the ZMQ\_PLAIN\_USERNAME and ZMQ\_PLAIN\_PASSWORD socket options. Which peer binds, and which connects, is not relevant.

## SEE ALSO

[**zmq\_setsockopt**(3)](/zmq_setsockopt/3.md) [**zmq\_null**(7)](/zmq_null/7.md) [**zmq\_curve**(7)](/zmq_curve/7.md) [**zmq**(7)](/zmq/7.md)

## AUTHORS

This page was written by the 0MQ community. To make a change please read the 0MQ Contribution Policy at **http://www.zeromq.org/docs:contributing**.