HELPER-MUX(8) User Contributed Perl Documentation HELPER-MUX(8)

# [NAME](#NAME)

helper-mux - Concurrency protocol multiplexer for Squid helpers

# [SYNOPSIS](#SYNOPSIS)

**helper-mux** helper-path \[helper-options ...]

# [DESCRIPTION](#DESCRIPTION)

**helper-mux** purpose is to relieve some of the burden **squid** has when dealing with slow helpers. It does so by acting as a middleman between **squid** and the actual helpers, talking to **squid** via the multiplexed variant of the helper protocol and to the helpers via the non-multiplexed variant.

Helpers are started on demand, and in theory the muxer can handle up to 1k helpers per instance. It is up to **squid** to decide how many helpers to start.

The helper can be controlled using various signals: - SIGHUP: dump the state of all helpers to STDERR

# [OPTIONS](#OPTIONS)

[**helper-path**](#helper)

Path to the helper being multiplexed.

[**helper-options**](#helper~2)

Command line options for the helper being multiplexed.

# [KNOWN ISSUES](#KNOWN_ISSUES)

**helper-mux** knows nothing about the actual messages being passed around, and as such cannot yet compensate for broken helpers.

It is not yet able to manage dying helpers.

# [COPYRIGHT](#COPYRIGHT)

```
 * Copyright (C) 1996-2026 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
   Copyright (C) Francesco Chemolli <kinkie@squid-cache.org>
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
```

2026-06-07 perl v5.42.2

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Document: helper-mux(8) from squid 7.6-r0 (Chainguard OS)
Source: https://github.com/squid-cache/squid.git