To set up SPF and DKIM for Zimbra, Follow the steps given below:
SPF defines a list of the servers, services, and IP addresses that are allowed to be relaying or sending email from your domain. You will have to manually add the IP address of your Zimbra server to your SPF record. The SPF record mechanism used for Zimbra is shown below, replace the “x.x.x.x” with your IP address.
v=spf1 ip4:x.x.x.x -all
If you are also using Google to send mails, both the entries should be added in your SPF record, Please refer the example below.
v=spf1 ip4:x.x.x.x include:spf.google.com -all
DKIM: You will have to enable DKIM on the Zimbra server. For enable DKIM on Zimbra, please click on the button below.