Shorewall Requirements

Tom Eastep

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This article applies to Shorewall 4.3 and later. If you are running a version of Shorewall earlier than Shorewall 4.3.5 then please see the documentation for that release.

Shorewall Requires:

  • A Linux kernel that supports Netfilter (No, it won't work on BSD or Solaris). I've tested with 2.4.2 - 2.6.16. Check here for kernel configuration information.

  • iptables 1.2 or later (but I recommend at least version 1.3.3)

  • Iproute (“ip” and "tc" utilities). The iproute package is included with most distributions but may not be installed by default. The official download site is

  • A Bourne shell or derivative such as bash or ash. This shell must have correct support for variable expansion formats ${variable%pattern}, ${variable%%pattern}, ${variable#pattern} and ${variable##pattern}.

  • Your shell must produce a sensible result when a number n (128 <= n <= 255) is left shifted by 24 bits. You can check this at a shell prompt by:

    • echo $((128 << 24))

    • The result must be either 2147483648 or -2147483648.

  • The firewall monitoring display is greatly improved if you have awk (gawk) installed.

  • On the system where the Shorewall package itself is installed, you must have Perl installed (preferably Perl 5.8.10):

    • If you want to be able to use DNS names in your Shorewall6 configuration files, then Perl 5.10 is required together with the Perl Socket6 module.

    • Perl Cwd Module

    • Perl File::Basename Module

    • Perl File::Temp Module

    • Perl Getopt::Long Module

    • Perl Carp Module

    • Perl FindBin Module

    • Perl Scalar::Util Module