Shorewall Requirements

Tom Eastep

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This article applies to Shorewall 3.0 and later. If you are running a version of Shorewall earlier than Shorewall 3.0.0 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.

Shorewall-perl Requirements

Shorewall-perl is a re-implementation of the Shorewall configuration compiler written in Perl. It is much faster than the classic Shorewall-shell compiler and produces a firewall script that runs much faster. It's prerequisites are described in the Shorewall-perl article.