Most of the time, when you want to send e-mail notifications to users about new Incidents, Service Requests, Activity assignments or pending reviews, an anonymous SMTP will suffice.
But often enough, anti-spam system may not like those ‘external e-mails’ and may toss them into your trash folder, for example.
And you may also want it to have a nice display name, instead of the e-mail only.
The answer for that is to use integrated authentication. This sounds simple enough. However, the interface is a bit dry:
Notice that it only says Windows Integrated. The big question is: which account will be used to log on to Exchange?
The answer is simple: the workflow account. There. Now, in order for it to work, you just need to make sure this account is mail enabled and that it can Send As the account you select above (helpdesk@, for example).
And there you go!
Hope it helps!