# perldoc > Log::Log4perl::Filter::MDC

## NAME
    [Log::Log4perl::Filter::MDC](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AFilter%3A%3AMDC/markdown) - Filter to match on values of a MDC key

## SYNOPSIS
        log4perl.filter.Match1               = [Log::Log4perl::Filter::MDC](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AFilter%3A%3AMDC/markdown)
        log4perl.filter.Match1.KeyToMatch    = foo
        log4perl.filter.Match1.RegexToMatch  = bar

## DESCRIPTION
    This Log4perl filter checks if a predefined MDC key, as set in "KeyToMatch", of the currently
    submitted message matches a predefined regex, as set in "RegexToMatch".

## SEE ALSO
    [Log::Log4perl::Filter](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AFilter/markdown), [Log::Log4perl::Filter::Boolean](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AFilter%3A%3ABoolean/markdown), [Log::Log4perl::Filter::LevelMatch](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AFilter%3A%3ALevelMatch/markdown),
    [Log::Log4perl::Filter::LevelRange](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AFilter%3A%3ALevelRange/markdown), [Log::Log4perl::Filter::MDC](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AFilter%3A%3AMDC/markdown),
    [Log::Log4perl::Filter::StringMatch](https://www.chedong.com/phpMan.php/perldoc/Log%3A%3ALog4perl%3A%3AFilter%3A%3AStringMatch/markdown)

## LICENSE
    Copyright 2002-2013 by Mike Schilli <<m@perlmeister.com>> and Kevin Goess <<cpan@goess.org>>.

    This library is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself.

## AUTHOR
    Please contribute patches to the project on Github:

        <http://github.com/mschilli/log4perl>

    Send bug reports or requests for enhancements to the authors via our

    MAILING LIST (questions, bug reports, suggestions/patches): <log4perl-devel@lists.sourceforge.net>

    Authors (please contact them via the list above, not directly): Mike Schilli
    <<m@perlmeister.com>>, Kevin Goess <<cpan@goess.org>>

    Contributors (in alphabetical order): Ateeq Altaf, Cory Bennett, Jens Berthold, Jeremy Bopp,
    Hutton Davidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco, Anthony Foiani, James FitzGibbon,
    Carl Franks, Dennis Gregorovic, Andy Grundman, Paul Harrington, Alexander Hartmaier David Hull,
    Robert Jacobson, Jason Kohles, Jeff Macdonald, Markus Peter, Brett Rann, Peter Rabbitson, Erik
    Selberg, Aaron Straup Cope, Lars Thegler, David Viner, Mac Yang.