Block messages from a specific e-mail address:
Set-SenderFilterConfig -BlockedSenders example@contoso.com,example2@contoso.com
Block messages from a specific domain:
Set-SenderFilterConfig -BlockedDomains contoso.com
Block messages from a specific domain and all subdomains:
Set-SenderFilterConfig -BlockedDomainsAndSubdomains contoso.com
Add a sender or domain to a previously created blocked list:
The examples above replace the current list of blocked senders. If you have previously configured your list and would like to add a sender or domain you can use the following commands to avoid having to retype your entire list.
$Configuration = Get-SenderFilterConfig
$Configuration.BlockedSenders += "example@contoso.com"
$Configuration.BlockedDomains += "contoso.com"
Set-SenderFilterConfig -BlockedSenders $Configuration.BlockedSenders -BlockedDomains $Configuration.BlockedDomains
Block messages that don't specify a sender:
Set-SenderFilterConfig -BlankSenderBlockingEnabled $true