To authorize Zimbra to send emails on your behalf you will have to manually add the IP address of your Zimbra server to your SPF record.
For example, if your Zimbra server is the only allowed email sender for your domain, your SPF record should look like the following. Replace the x.x.x.x with your IP address.
v=spf1 ip4:x.x.x.x ~all
If you let's say are also using Google to send email, both of these services have to be authorized in your SPF record as such:
v=spf1 ip4:x.x.x.x include:_spf.google.com ~all
To authenticate your emails and further increase the chances of your emails ending up in your recipient's inboxes rather than spam, you will have to enable DKIM on the Zimbra server.
For instructions on how to do that, please click on the button below.
Check if DKIM is configured correctly
Why not use our free Investigate tool to swiftly verify your DKIM configuration.
Create a free OnDMARC account to test your configuration.