Does Dreamhost support Tagged Message Delivery Agent (TMDA) installed on our mail servers?
Anything that can be installed under your home directory and invoked via procmail or a forward can probably be made to work on our system. We don’t support it officially though, no.
- DreamHost Head Honcho/Founder
Difficult to get working well, though it has been done. I would personally suggest having a good read of some of the reasons why C/R systems are bad, bad, bad.
There are a few past threads on the subject; search in all past posts iin all forums for TMDA. I did some of the work for you - here are links to some past posts explaining all of this in more detail.
$recipient_delimiter still doesn’t work with virtual domains on the version of Postfix that DreamHost is running. Also, when the junk filter is enabled, there’s no way (that I’m aware of) to make this work since the junk mail filter has no concept of users, and (I’m pretty sure) would reject mail for email@example.com, even if firstname.lastname@example.org is a valid address.
There are third party C/R services which can work with external email accounts; I would especially NOT recommend these, though (even more than I don’t recommend C/R in general).
This is just my opinion, though.
Aside from the technical problems, the C/R thing irritates me because you’re basically saying “I don’t care if I’m generating more junk [in the form of backscatter] headed towards OTHER people, and I’m so important that people should spend extra time to confirm their messages to me.” Not only that, but C/R has problems dealing with legitimate emails that aren’t sent by a human. Not everyone wants / needs to receive such emails in all situations, but most people do. It doesn’t scale well - imagine the problems if everyone uses it.
I do think that there are systems which do a good job at reducing a lot of the problems associated with C/R, and TMDA is one of the best in that regard. I still don’t think it’s appropriate for general use, though.
Some past discussion: