OutlookHeaders Add-in

Microsoft Office Outlook add-in for modifying mail headers & outbound emails.

Description

OutlookHeaders is a simple Microsoft Outlook add-in for Windows that allows to adjust outbound email messages.

Overall this add-in can do the following:

Add arbitrary http headers to your outbound email messages.
Overwrite mail client name, so that your email doesn't appear to have come from Microsoft Outlook.
Suppress initial received: header, to prevent inclusion of the public IP address where the email was composed. (Outlook by default adds your public IP to every message.)
Adjust the format of your replies and forwarded emails to plaintext, or HTML, regardless of the format of the original message.
At the same time, if adjusting the format of an email to HTML, this add-in allows to adjust the Cascading Style Sheets (or CSS) for it.
This add-in also allows to automatically remove the tracking pixel from your replies and forwarded emails for specific domains.
All options listed above can be applied per individual email account, or for all accounts in Outlook.
This add-in supports automated installation, which allows to set it up from a pre-configured file.
This add-in supports non-interactive installation in an Active Directory environment, or on a corporate network via Group Policy Objects (or GPOs.)

Screenshot

Manual

To learn more about this add-in, check its official manual.

Release Build

If you don't want to build and code-sign this add-in yourself, you can download the latest release build here.

Prerequisites

Microsoft Outlook 2007 for Windows, or later
Microsoft .NET Framework 3.5
Visual Studio 2010 Tools for Office Runtime

Build Instructions

The original intentions of making this add-in was to make it backward compatible with older versions of Microsoft Office. (The earliest I chose was Office 2007.) That is why to build this add-in I had to use older versions of the Visual Studio and the .NET Framework.

There are four Visual Studio solutions that are involved in building this add-in. Each has to be built in this particular order:

OutlookHeaders Solution (OutlookHeaders.sln file) was originally designed and built in Visual Studio 2008, SP1 v.9.0

This solution contains the OutlookHeaders project with the actual code for this add-in. It's written in C#. This project requires the following references to be able to work with the Office components:
- Microsoft.Office.Interop.Outlook
- Microsoft.Office.Tools.Common.v9.0
- Microsoft.Office.Tools.Outlook.v9.0
- Microsoft.Office.Tools.v9.0
- Microsoft.VisualStudio.Tools.Applications.Runtime.v9.0
- Office
- System.AddIn
The OutlookHeaders project in this solution had the Post-Build event that would sign the resulting OutlookHeaders.dll, as the $(TargetPath) file, with our code-signing certificate. Thus, to be able to load it into the Outlook without seeing a security warning, you will need to provide your own code-signing certificate to digitally sign it. Without digitally signing your add-in Microsoft Office may refuse to load your add-in. For organizations, I believe there is a way to self-sign your office add-ins.
CustomActionOutlookHeadersInstaller Solution (CustomActionOutlookHeadersInstaller.sln file) was originally designed and built in Visual Studio 2010 v.10.0

This solution contains the CustomActionOutlookHeadersInstaller project with the code for the custom actions for the MSI installer. It is written in C#. The project requires the following references to interface with the WiX installer:
- Microsoft.Deployment.WindowsInstaller (included in the WiX Toolset library)
The CustomActionOutlookHeadersInstaller project in this solution had the Post-Build event that would sign the resulting CustomActionOutlookHeadersInstaller.CA.dll, as the $(TargetDir)$(TargetName).CA$(TargetExt) file, with our code-signing certificate. This signature was provided only to establish end-user trust and is not required for this add-in to be loaded into Microsoft Office.
OutlookHeadersInstaller Soltution (OutlookHeadersInstaller.sln file) was originally designed and built in Visual Studio 2010 v.10.0 as a Setup Project built with the use of the WiX Toolset library v.3.7.

This solution contains the OutlookHeadersInstaller project with the Windows Installer XML markup to build the main MSI installer for this add-in, that provides code to install, uninstall, repair and upgrade it on client workstations. The project requires the following references to the WiX library components:
- WixNetFxExtension
- WixUtilExtension
The OutlookHeadersInstaller project in this solution had the Post-Build event that would sign the resulting OutlookHeadersInstaller.msi, as the $(TargetPath) file, with our code-signing certificate. (Only SHA-1 signature was used to provide compatibility with MSI signing limitations.) This signature was provided only to establish end-user trust and is not required for this add-in to be loaded into Microsoft Office.
BootstrapperOutlookHeaders Soltution (BootstrapperOutlookHeaders.sln file) was originally designed and built in Visual Studio 2010 v.10.0 as a Bootstrapper Project, built with the use of the WiX Toolset library v.3.7.

This solution contains the BootstrapperOutlookHeaders project with the XML markup to build the Bootstrapper installer for this add-in to be able to install needed prerequisite components (listed above). The project requires the following references to the WiX library components:
- WixBalExtension
- WixNetFxExtension
- WixUtilExtension
The BootstrapperOutlookHeaders project in this solution had the Post-Build event that would de-construct and sign components of the resulting bootstrapped installer. This was necessary to pass the required bootstrapper authentication of the engine.exe and is not necessary for this add-in to be loaded into Microsoft Office. The following commands were provided:
```
del "%tmp%\engine.exe"
"C:\Program Files (x86)\WiX Toolset v3.7\bin\insignia.exe" -ib "$(TargetFileName)" -o "%tmp%\engine.exe"
command-to-code-sign "%tmp%\engine.exe"
"C:\Program Files (x86)\WiX Toolset v3.7\bin\insignia.exe" -ab "%tmp%\engine.exe" "$(TargetFileName)" -o "$(TargetFileName)"
command-to-code-sign "$(TargetPath)"
del "%tmp%\engine.exe"
```
where command-to-code-sign must be replaced with your own command to digitally code-sign that specific file.

NOTE: This lame GitHub restriction doesn't allow me to push vstor_redist.exe via the web interface into "OutlookHeaders\Installer\OutlookHeadersInstaller\OutlookHeadersInstaller\Sources", which is larger than 25MB. Download it yourself from here.

Installation

The reason we're building several versions of the installer is to provide for different ways of application of this add-in:

The bootstrapper installer (labeled for end-users as "Bundled Installer") is an easy way to install the add-in with a possibility to download and install all needed prerequisited in a single UI package.
The standalone MSI installer is a light-weight version, that was designed to support non-interactive installation on multiple workstations, such as Microsoft Active Directory, via Group Policy Objects. But it requires for all prerequisite components (listed above) to be already present on the workstations.

Check here for details of the installation.

Submit suggestions & bug reports here.

dennisbabkin/OutlookHeaders-Add-in