how to block outgoing mails and allow only our domain mails?

[lance]

how to block outgoing mails and allow only our domain mails(ourcompanyname.com) we using Mozilla thunderbird.

[imfirewall]

If your company email server is in a dedicated email server with a static ip address, there is a simple solution to whitelist your email server: "block all email protocols, block webmail and add your email server into the exception list."

Attached files

[imfirewall]

If your company email is in a shared email server, you need to enable "email black & white list", following below steps:

1. Block "SMTP over SSL" protocol

2. Block web mail

3. Enable white list for local email senders

4. Save and apply configuration

Attached files