How can I block email from a sender? Unfortunately, NG Firewall does not provide a means of blocking email from a specific sender. This is something you would do on your email server. Follow Have more questions? Submit a request Comments 2 comments Article is closed for comments. Belal Gouda April 23, 2019 10:39 how to block email address of a sender to send to our domain Tiffany April 23, 2019 13:43 Belal, Unfortunately this is not possible within Untangle. You will need to do any blacklisting on your email server.