Squid on Windows

Does Squid run on Windows ?

Squid can compile and run on Windows as a system service using the Cygwin emulation environment, or can be compiled in Windows native mode using the MinGW + MSYS development environment. Windows NT 4 SP4 and later are supported.

On Windows 2000 and later the service is configured to use the Windows Service Recovery option restarting automatically after 60 seconds.

  • {i} The original development code name of the 2.5 project port was SquidNT, but after the 2.6.STABLE4 release, this project was complete. So when speaking about Squid on Windows, people should always refer to Squid, instead to the old SquidNT name.

Known Limitations

  • Squid features not operational:
    • DISKD: still needs to be ported
    • Transparent Proxy: missing Windows non commercial interception driver
    • WCCP: these features have not been ported. Without transparent proxy support there is no need or use.
    • SMP support: Windows equivalent of UDS sockets has not been implemented
  • Some code sections can make blocking calls.
  • Some external helpers may not work.
  • File Descriptors number hard-limited to 2048 when building with MinGW.
  • Squid-3.x of all formal releases have major build issues.

Pre-Built Binary Packages

Packages available for Squid on multiple environments.


Bug Reporting: see https://cygwin.com/problems.html

Binary packages for the Cygwin environment on Windows are at:


Maintainer: GuidoSerassio of Acme Consulting S.r.l.

Bug Reports: http://bugs.squid-cache.org/

  • {X} NOTE: this package is experimental and known to contain major bugs.

Binary packages built using the Microsoft toolchain for Windows NT/2000/XP/2003 are at http://squid.acmeconsulting.it/

Squid-2.7 / Squid-2.6

Maintainer: GuidoSerassio of Acme Consulting S.r.l.

Bug Reports: http://bugs.squid-cache.org/

Binary packages built using the Microsoft toolchain for Windows NT/2000/XP/2003 are at http://squid.acmeconsulting.it/

Installing Squid


Some new command line options were added for the Windows service support:

  • -n switch to specify the Windows Service Name. Multiple Squid service instances are allowed. Squid is the default when the switch is not used. All service control operations use this switch to identify the destination instance being targeted.

  • -i switch to install the Windows service. It's possible to use -f switch at the same time to specify a different squid.conf file for the Squid Service that will be stored on the Windows Registry. To install the service, the syntax is:

squid -i [-f file] [-n service-name]
  • -r switch will uninstall the Windows service. Use the appropriate -n switch to determine which service instance is being removed. To uninstall the service, the syntax is:

squid -r [-n service-name]
  • -k switch is not new, but requires the use of -n to target the service instance. The syntax is:

squid -k command [-f file] [-n service-name]

Command Line

To use the Squid original command line, the new -O switch must be used ONCE, the syntax is:

squid -O cmdline [-n service-name]

If multiple service command line options must be specified, use quote. The -n switch is needed only when a non default service name is in use.

  • {X} Don't use the "Start parameters" in the Windows 2000/XP/2003 Service applet. They are specific to Windows services functionality and Squid is not able to interpret and use them.

In the following example the command line of the "squidsvc" Squid service is set to "-D -u 3130":

squid -O "-u 3130" -n squidsvc

Cache Manager CGI on Windows

On Windows, cache manager can be used with Microsoft IIS or Apache. Some specific configuration could be needed:

  • IIS 6 (Windows 2003):
    • On IIS 6.0 all CGI extensions are denied by default for security reason, so the following configuration is needed:
      • Create a cgi-bin Directory
      • Define the cgi-bin IIS Virtual Directory with read and CGI execute IIS permissions, ASP scripts are not needed. This automatically defines a cgi-bin IIS web application
      • Copy cachemgr.cgi into cgi-bin directory and look to file permissions: the IIS system account and SYSTEM must be able to read and execute the file
      • In IIS manager go to Web Service extensions and add a new Web Service Extension called "Squid Cachemgr", add the cachemgr.cgi file and set the extension status to Allowed
  • Apache:
    • On Windows, cachemgr.cgi needs to create a temporary file, so Apache must be instructed to pass the TMP and TEMP Windows environment variables to CGI applications:

ScriptAlias /squid/cgi-bin/ "c:/squid/libexec/"
<Location /squid/cgi-bin/cachemgr.cgi>
    PassEnv TMP TEMP
    Order allow,deny
    Allow from workstation.example.com

Configuration Guides

These and many other general manuals in the ConfigExamples section.

Registry DNS lookup

On Windows platforms, if no value is specified in the dns_nameservers option in squid.conf or in the /etc/resolv.conf file, the list of DNS name servers are taken from the Windows registry, both static and dynamic DHCP configurations are supported.

Compatibility Notes

  • It's recommended to use '/' char in Squid paths instead of '\'
  • Paths with spaces (like 'C:\Programs Files\Squid) are NOT supported by Squid
  • When using ACL like 'acl aclname acltype "file"' the file must be in DOS text format (CR+LF) and the full Windows path must be specified, for example:

acl blocklist dstdomain "c:/squid/etc/blocked1.txt"
  • The Windows equivalent of '/dev/null' is 'NUL'
  • Squid doesn't know how to run external helpers based on scripts, like .bat, .cmd, .vbs, .pl, etc. So in squid.conf the interpreter path must be always specified, for example:

url_rewrite_program c:/perl/bin/perl.exe c:/squid/libexec/redir.pl
url_rewrite_program c:/winnt/system32/cmd.exe /C c:/squid/libexec/redir.cmd
  • When Squid runs in command line mode, the launching user account must have administrative privilege on the system
  • "Start parameters" in the Windows 2000/XP/2003 Service applet cannot be used
  • On Windows Vista and later, User Account Control (UAC) must be disabled before running service installation


When running configure, --disable-wccp and --disable-wccpv2 options should always specified to avoid compile errors.

New configure options:

  • --enable-win32-service

Updated configure options:

  • --enable-arp-acl
  • --enable-default-hostsfile

Unsupported configure options:

  • --enable-coss-aio-ops: On Windows Posix AIO is not available
  • --with-large-files: No suitable build environment is available on both Cygwin and MinGW, but --enable-large-files works fine

Compiling with Cygwin

In order to compile Squid, you need to have Cygwin fully installed.

The usage of the Cygwin environment is very similar to other Unix/Linux environments, and -devel version of libraries must be installed.

  • /!\ WCCP is not available on Windows so the following configure options are needed to disable them:



Squid will by default, install into /usr/local/squid. If you wish to install somewhere else, see the --prefix option for configure.

Now, add a new Cygwin user - see the Cygwin user guide - and map it to SYSTEM, or create a new NT user, and a matching Cygwin user and they become the squid runas users.

Read the squid FAQ on permissions if you are using CYGWIN=ntsec.

When that has completed run:

squid -z

If that succeeds, try:

squid -N -D -d1

Squid should start. Check that there are no errors. If everything looks good, try browsing through squid.

Now, configure cygrunsrv to run Squid as a service as the chosen username. You may need to check permissions here.

Compiling with MinGW

In order to compile squid using the MinGW environment, the packages MSYS, MinGW and msysDTK must be installed. Some additional libraries and tools must be downloaded separately:

Before building Squid with SSL support, some operations are needed (in the following example OpenSSL is installed in C:\OpenSSL and MinGW in C:\MinGW):

  • Copy C:\OpenSSL\lib\MinGW content to C:\MinGW\lib
  • Copy C:\OpenSSL\include\openssl content to C:\MinGW\include\openssl
  • Rename C:\MinGW\lib\ssleay32.a to C:\MinGW\lib\libssleay32.a

Unpack the source archive as usual and run configure.

The following are the recommended minimal options for Windows:

Squid-2 :


Squid-3 : (requires Squid-3.5 or later, see porting efforts section below)


Then run make and install as usual.

Squid will install into c:\squid. If you wish to install somewhere else, change the --prefix option for configure.

When that has completed run:

squid -z

If that succeeds, try:

squid -N -D -d1
  • squid should start. Check that there are no errors. If everything looks good, try browsing through squid.

Now, to run Squid as a Windows system service, run squid -n, this will create a service named "Squid" with automatic startup. To start it run net start squid from command line prompt or use the Services Administrative Applet.

Always check the provided release notes for any version specific detail.

Squid-3 porting efforts

Squid series 3 has major build issues on all Windows compiler systems. Below is a summary of the known status for producing a useful Squid 3.x for Windows.

The TODO list for Windows


Sponsorship from iCelero produced a working Squid-3.2 and Squid-3.3. Unfortunately the product and sponsorship dropped before the final stages of this work could be cleaned up for GPL release.

As of Squid-3.5 :

  • the default feature set builds without extra special ./configure options.
  • missing shared socket support available in Vista and later. Necessary for SMP workers.

AmosJeffries is cross-compiling with Mingw-w64 build environment on Debian, with occasional native MinGW environment builds for confirmation of changes. As this is spare-time work progress is slow.

# Debian Packages Required:
# g++
#       provides GCC base compiler. GCC 4.9.1 or later required.
# mingw-w64
#       provides GCC cross-compiler. GCC 4.9.1 or later required.
# mingw-w64-tools
#       provides pkg-config and other build-time tools used by autoconf

./configure \
        --host=i686-w64-mingw32 \
        CXXFLAGS="-DWINVER=0x601 -D_WIN32_WINNT=0x601" \
        CFLAGS="-DWINVER=0x601 -D_WIN32_WINNT=0x601" \
        BUILDCXX="g++" \
        --enable-build-info="Windows (MinGW cross-build)"

There also appears to be some work done by Joe Pelaez Jorge (https://code.launchpad.net/~joelpelaez/squid/win32).

There are additional wishlist items that also need to be sorted out:

  • Separate Windows AIOPS logics from Unix AIO logics. The two are currently mashed together where they should be in separate conditionally built library modules.
  • Windows OIO support. Alternative to Unix AIO and AIOPS disk I/O functionality.
  • Building an installer


Packages http://sourceware.mirrors.tds.net/pub/sourceware.org/cygwin/x86/release/squid/ There have been unconfirmed reports from some users of building up to Squid-3.3 successfully and producing a usable executable. Cygwin project provide version 3.3.3 packages.

As of Squid-3.4 the latest confirmed details is that there are significant build errors (bug 4037). Assistance fixing this bugs issues is welcome, note that many of the build issues known are shared with MinGW and may be fixed as that work continues (or made worse).

Visual Studio

Almost no work on this environment has been done since Squid-2.7.

Entirely new .sln, .sdf and .vcxproj build files need to be generated. Ideally these would mirror the on-Windows style of convenience libraries assembled to produce a number of different binaries. Experiments along those lines have some nice results, but issues with BZR on Windows are causing trouble. The Squid developers are discussing moving to git, which will hopefully resolve the main issue there.



KnowledgeBase/Windows (last edited 2014-10-13 14:48:53 by Amos Jeffries)