This page applies to new clients connecting with Mimecast using the Connect Application with an On Premise or Hybrid exchange. If you are using an Office 365 exchange, see the Connect Application: Securing Your Inbound Email (Office 365) page. If you're not using the Connect Application, click here.
Once you have completed all the Connect Application tasks, you must lock down your organization's firewall on port 25 to the Mimecase Data Center IP Ranges. The Connect Application will display the relevant IP Ranges for your account.
This ensures your emails are scanned by the Mimecast security systems to prevent viruses and spam from reaching your internal environment.
- Ensure all emails are being delivered by Mimecast only, before locking down your firewalls.
- Remove any other MX Records.
Once you have locked down your firewall, you can run the firewall test from the Connect Application to determine if the lockdown was successful.
If your firewall is managed by a third party provider, you'll need to provide them the IP Ranges so they can lock down the firewall for you.