Switching to the email gateway will involve one of three methods:
- If a corporate firewall is in use, then change the firewall configuration to forward SMTP traffic (port 25) to the email gateway .Ensure that traffic for any external services such as Razor or Pyzor is directed to the email gateway. Firewall details for external services are given in Chapter 13.
- Give the email gateway the IP address of the old email server. To do this, give the original email server a new IP address and give the new email gateway the IP address of the original email server. Alter the email gateway configuration to use the new IP address.
- Alter the DNS MX records for the domain. Make the current email server the new backup MX, and the new gateway the primary ...