Inbound and outbound mail flow must work in order to complete the setup.

In general there are two possibilities:

• Inline scenarios (A and B)
• Parallel scenarios (C, D and Z)

Inline scenarios (A and B)

In these scenarios, you need to focus on preparing the firewall to allow the mail flow inbound and outbound to the seppmail.cloud hosts and finally change the MX record.

1. Set TTL of MX record to 1 hour.
2. Set up mail hosts in the seppmail.cloud portal to point to mail hosts of on-premises infrastructure.
3. Prepare firewalls to allow communication between on-premises infrastructure and the seppmail.cloud for your region.
4. Change outbound mail flow to seppmail.cloud.
5. Change MX record to seppmail.cloud for inbound traffic.
6. Enable E-mail transport in seppmail.cloud.

Parallel scenarios (C, D and Z)

You need to configure your mail filter in a way that mails flow always through the seppmail.cloud for cryptographic processing but do not create loops.

For on-premises mail filters you also need to configure your firewall to allow communication to and from seppmail.cloud.

Steps would be:

1. Set up mail hosts in the seppmail.cloud portal.
2. Prepare mail transport to let mails flow through the seppmail.cloud and avoid mail loops.
3. Prepare firewalls to allow communication between on-premises infrastructure and the seppmail.cloud for your region.
4. Enable transport rules to send mails through seppmail.cloud.
5. Enable E-mail transport in seppmail.cloud.