Whitelist in Exchange

Open Exchange Management Shell

To check whats currently whitelisted (Bypassed Recipients):

To whitelist a single email address:

$list = (Get-ContentFilterConfig).BypassedSenders

$list.add("new.mail@address.com")

Set-ContentFilterConfig -BypassedSenders $list

To whitelist an entire domain:

$list = (Get-ContentFilterConfig).BypassedSenderDomains

$list.add("domain.com")

Set-ContentFilterConfig -BypassedSenderDomains $list