Sender Domain Check

[brschool]

What happens if I uncheck the box "Client Must Have Relaying Access" in the Sender Domain Check Section

With it checked many places cannot send emails to me even from my workplace they do not come through
David

[Code Crafters]

Sender Domain Check checks mails from a sender on a locally (AMS) hosted domain. This is to stop fake emails from your local domain. You must choose one or both of the following options:

Client Must Have Relaying Access - Generally any of your users sending via AMS should always be logging into the outgoing mail server with SMTP authentication to gain relaying access to send to external domains. This check will refuse the mail if they haven't.

Sender Email Address Must Exist Locally - This checks that the sender email address at least exists locally for your hosted domains. This is very good at stopping spoof attempts which try to guess email addresses on your domain.

Note: SPF also does a similar job of protecting your local domains from having spoofed emails sent from unauthorised senders.