Gmail "via"

When you are sending emails to accounts on the gmail system there is a chance that the FROM line of the email will say:

From: Chris via YourSendingService

Gmail checks whether emails are correctly authenticated. If your messages are sent by a bulk mailing vendor or by third-party affiliates, publish an SPF record that includes the IPs of the vendor or affiliates which send your messages and sign your messages with a DKIM signature that is associated with your domain.