Most firewalls block or restrict traffic to limit access to only necessary users and services. If you restrict traffic in your environment, you must add the IP address ranges in this guide to your list of trusted IP addresses to allow traffic to and from the required services.

A firewall is a part of a computer or network that is designed to block unauthorized access while permitting outward communication.

• Ingress traffic originates outside of a business' routers and travels to a destination inside of the business' network
  • Example: An ingress email originates outside of a business' computer network, is passed over the internet and then enters the business' network before it's delivered to the recipient
    

• Egress traffic begins inside of a business' network and travels through its routers to a destination outside of the network
  • Example: An egress email email travels from a user's computer and passes through a business' network routers before it is delivered to the internet to travel to a final destination