Add the following TXT record in your domain’s DNS Manager:
v=spf1 a mx include:_spf.google.com ~all
You can leave the hostname field blank. If your DNS manager isn’t letting you leave it blank, put “@” in that field without quotes.
- Go to https://www.google.com/a/cpanel/example.com/
- Go to Advanced Tools > Authenticate email > Set up email authentication (DKIM)
- Generate new DKIM key and place it as a TXT record in your DNS manager.
- Wait for few hours for DNS propagation and verify the DKIM keys in your Google Apps Cpanel.
Google’s definition to SPF and DKIM:
- SPF record: An SPF record is a list of IP addresses that are authorized to send mail for a particular domain. For more information on how to publish an SPF record, please visit http://www.openspf.net.
- DKIM: DKIM (DomainKeys Identified Mail) is a way to digitally sign messages and verify that the messages were sent by a particular domain. It works like a wax seal on an envelope, preventing messages from being tampered with.
Tools to verify SPF and DKIM
- http://mxtoolbox.com/ (use syntax in search box like spf: example.com)