Use Multiple From: Addresses with a Mac OS X Mail Account
To set up multiple addresses for one account in Mac OS X Mail:
- Select Mail | Preferences... from the menu in Mac OS X Mail.
- Go to the Accounts category.
- Highlight the desired account.
- Enter all email addresses you want to use with this account in the Email Address: field.
- Separate the addresses by commas (like "firstname.lastname@example.org,email@example.com").
After you have closed the configuration dialog and saved the new settings you can send mail from all these email addresses.
Additional Addresses Disappear When You Relaunch Mac OS X Mail?
Unfortunately, you cannot add alternative addresses to .Mac email accounts in Mail. You can, however, set up your .Mac account as an IMAP account (use "mail.mac.com" as the IMAP and "smtp.mac.com" as the SMTP server as well as your .Mac user name and password) and add alternative addresses to that account.