How do I allow inbound mail from Email Threat Protection in Google Workspace?

During this process, you will:

1. Sign into the G Suite admin console.
2. Select Apps > Google Workspace > Gmail > "Spam, Phishing and Malware".
3. Hover over "Inbound Gateway" and select CONFIGURE or click Edit to edit an existing one.
4. Enter a description, such as Zix inbound gateway.
5. Under Gateway IPs, select ADD and enter the appropriate IPs. 
   • 199.30.235.11/32
   • 74.203.185.12/32
   • 5.152.184.128/25
   • 5.152.185.128/26
   • 8.19.118.0/24
   • 8.31.233.0/24
   • 69.20.58.224/28
   • 5.152.188.0/24
   • 199.187.164.0/24
   • 199.187.165.0/24
   • 199.187.166.0/24
   • 199.187.167.0/24
   • 69.25.26.128/26
   • 204.232.250.0/24
6. Check Automatically detect external IP (recommended).
7. Customers who have routed all their inbound mail through a Zix system may wish to check Reject all mail not from gateway IPs.
8. Select ADD SETTING.
9. Select SAVE in the bottom right hand corner.

Note: While not required in Google Workspace, you may wish to add the same IP addresses to the Email allowlist field. IPs added to the Inbound Gateway field should be treated as trusted hosts.