First of all, what is a whitelist ?
A whitelist is a list of known safe email senders. Whitelists can be made up of IP addresses, domain names, or email addresses. In most cases businesses will choose to whitelist domain names of highly trusted customers or suppliers, or email addresses that are the source of critical emails.
Whitelist features are not available via Exchange Management Console (the GUI), so this will have to be completed via the Exchange Powershell Open powershell via the exchange menu item and run one of the following scripts, based on your requirement:
To check whats currently whitelisted (Bypassed Recipients):
To whitelist a single email address:
$list = (Get-ContentFilterConfig).BypassedSenders
Set-ContentFilterConfig -BypassedSenders $list
To whitelist an entire domain:
$list = (Get-ContentFilterConfig).BypassedSenderDomains
Set-ContentFilterConfig -BypassedSenderDomains $list
And if you encounter any problems feel free to comment / contact me.