Sending email from Gmail without adding on the custom “Sender: youraccount@gmail.com” has been a long requested feature from users. So frequently requested was this feature that search results were flooded with complaints and requests even after Gmail provided a solution and announced it on their blog.
The solution is an enhancement to the “Send as” options that allow you to specify a different “From” address to your Gmail account. Within this is now an option to send the mail via your own server thus completely bypassing Gmail’s outbound SMTP, and thus your mail appears as if it were send from your own host.
For this to work you must have a SMTP account that will accept outgoing mail via Google’s servers (with or without authentication), and be able to verify that you own the email account (which is the same method of verifying that you receive a unique code that is emailed to the account).