I am using Mahara 1.3.3 clean install on shared hosting with inmotionhosting, linux php 5.3, mysql. Everything works, but my emails sent by mahara are getting blocked. I had the same problem with my moodle installation, but was able to configure it with SMTP email and a defined, working noreply address. However, this is not working with mahara.
The mail is actually sent, but is blocked at the destination because the user's profile email address is being used as the from field, instead of the noreplyaddress as defined. Since the email is coming from another domain, but claiming to be from the same domain as the recipient, it's blocked by the receiving mailserver (rightfully so).
In doing the testing, I was following the troubleshooting info on the wiki and using the contact us form to send the test emails. Peeking around the code I see that that is a rather "crude" form that takes the email given and passes it on to phpmailer as the from address. The from email field is autopopulated since I am logged in, so the noreplyaddress is never used in this case.
After fixing other problems, the contact form submissions still get blocked (obviously). In a case where the noreplyaddress config directive is set, the form should be smart enough to substitute that address for the entered address (or better yet-- apply that address to the reply-to address, and use the noreply address as the "from" or "sender" fields to comply with proper envelope format and accepted relay rules) since in effect mahara is using the mailserver as a relay.
If that can't be done, perhaps you could include a switch to turn off the contact form and replace it with a email address url for contact (mailto) so the person trying to contact the admin can use their own mail system (less ideal I guess).
Lastly, until this is fixed, and possibly after, the troubleshooting docs shouldn't suggest using this form to troubleshoot email since the form itself is the problem!
Forum post with complete details: http://mahara.org/interaction/forum/topic.php?id=3110#post13442
I'll have to think about this one a bit more because we personally do make use of the fact that the emails are made to appear as though they are sent by users directly.
For Mahara.org, we feed the contact us emails directly into an automated system (request tracker) which automatically emails the user back with a ticket number. We wouldn't want to break this.
However, maybe we should just forget about the whole mail form and just have a standard mailto: link.