Once configured it is a good practice to verify email servers SPF and DKIM records ensuring proper email deliverability. The process is very simple just send an email to check-auth@verifier.port25.com from the configured email server/domain and you will receive an email response with verification report in it. If things are configured correctly the report will show "PASS" as shown below.

Google Apps offers an excellent email service for businesses, anybody having a domain name can offer anyemail@theredomain.com email accounts with full Gmail features by just changing a few MX record entries in there DNS options and configuring there web-applications to use Google's server for emailing.

To ensure better email delivery rate to user's inbox avoiding chances of being tagged as SPAM, there are systems in place which allows email sending server to verify email origin (a sort of digital signature) and let SPAM categorization algorithms decide whether the email is sent from a fake "From" origin address or a real one.

Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) are two such measures and here is how to set them up for emails originating from Google Apps servers for your domain.