Turn off email read receipts. Hackers will gather information from your systems and know if you read the emails. It would also alert them that the email address is valid and since you opened it, they know it is a functioning path to get to you with a click link Trojan or virus or spear fishing attack.
Turn off your email out of office notifications. Most people are connected 24/7 and can respond to urgent requests. Sending out an out of office email will give away other emails or names for the hacker to attempt to contact. This also allows the hacker to know you are not in and they can time an email attack to when you return and maybe busy so you make a mistake and click a link that you normally wouldn’t.
If any of your software bounces back a response from a device you want to disable those notifications for external senders. Often the bounce notice gives away the software or hardware that is sending the message. Microsoft Outlook or Barracuda firewalls may give out information to the hacker on their next attack.
Remember, what software the company runs, and who is in those roles in the company can be valuable information for the next round of cyber attacks. Stay alert!