Running an outward facing server for contractors who's hostname is sub.example.com. The service needs to send mail to the contractors for various reasons (new projects, login details, etc). I have no intentions on making this machine an smtp server, and can successfully send mail through smtp.gmail.com, as I have Google Apps.
Trouble is, the emails go out as firstname.lastname@example.org, where is the account I use to authenticate to smtp.google.com to send the mail, when I'd like it to go out as email@example.com.
I supposed that could be looked upon as spoofing in a way, so I understand why this wouldn't readily be done.
Setting up sendmail with an smtp relay worked, but all the emails end up in junk folders during my test. This continued even after I setup SPF records for the subdomain on the root domain's dns.
It would be a lot of effort to setup and administer an smtp server just for this, as the mail volume won't be that serious. I can settle for sending mail from the root domain account through smtp.gmail if it's good practice (I can't remember if I've come across this before as a customer/user, even if I have that wouldn't mean it's good practice).
Which brings me to my question, albeit I've tried to remove any subjectiveness: Is it best practice to send the email with the matching domain as the service (firstname.lastname@example.org), or is sending from the root domain (email@example.com) just as acceptable?