Yes, Dreamhost offers all of IMAP+POP3+SMTP at "mail.yourdomain.com". It does require authentication of course, to prevent spammers from using the SMTP. But it's really nice for us normal users to be free from the ISP-provided SMTP which may have limitations. DreamHost SMTP is available on the standard 25 and 587 ports so even if your ISP blocks or limits port 25, you can still use DreamHost SMTP.
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