Scenario

You'd like to find out more about how the Exclaimer Outlook Add-In connects to the internet to download signatures. You have a restrictive firewall policy and need to whitelist the URLs used by the Add-In.

Resolution

The Exclaimer Outlook Add-In uses the following URLs - please add these to your firewall allow/exceptions list to ensure that the Exclaimer Outlook Add-In can connect successfully:

URL Purpose
login.microsoftonline.com Used to authenticate to Azure.
secure.aadcdn.microsoftonline-p.com Used to authenticate to Azure.

<region code>.outlooksignatures.exclaimer.net

(Where <region code> is replaced with the region code for the subscription, see: How to check your region code)

Used to download signature data.

appsforoffice.microsoft.com/lib/1.1/hosted/office.js

Runtime support.

static2.sharepointonline.com/files/fabric/office-ui-fabric-core/9.6.1/css/fabric.min.css

CSS for the display of the add-in user interface.

pro.fontawesome.com/releases/v5.10.0/css/all.css

CSS for the display of the add-in user interface.
outlookclient.exclaimer.net
Used for essential metadata, configuration settings, and permissions that define the Add-ins behavior, deployment, and integration with Office 365 services.
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