ZMQ\_PLAIN(7) 0MQ Manual ZMQ\_PLAIN(7)

# [NAME](#NAME)

zmq\_plain - clear-text authentication

# [SYNOPSIS](#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](#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](#SEE_ALSO)

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

# [AUTHORS](#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**.

10/24/2026 0MQ 4.3.5

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Document: zmq_plain(7) from zeromq 4.3.5-r14 (Chainguard OS)
Source: https://github.com/zeromq/libzmq