Traditionally, I've installed dovecot on my small-office server (traditionally by compiling manually and deploying to /usr/local but recently by way of SBO), mainly because I run SquirrelMail on my server and understood from their documentation that UW-IMAP would not work out of the box since it has by default disabled PLAIN login over unencrypted connections since 2002 to be compliant with RFC3501 security requirements, thereby making it incompatible with SquirrelMail out of the box as that product relies on PLAIN login.

However, as I'm always trying to keep software extraneous to the Slackware DVD off my server (since it's a very light-load server and not what I would call "mission critical" or even "production" :P), I toyed around with UW-IMAP again today and noticed that it *was* working with SquirrelMail out of the box on Slackware.

Thinking that was strange, I dived into the SlackBuild and it looks like Slackware purposely builds UW-IMAP to be non-RFC3501 compliant and does allow PLAIN login on insecure sessions.

Given the Slackware philosophy as I've understood it to distribute binaries as the developers intended where possible, I'm wondering if anyone knows the reason for the decision to build it this way? Is it just in the interests of backwards-compatibility? I can't really find a paper-trail in old ChangeLogs.

I don't know the answer to your question. I downloaded the source and played around. I couldn't even get a connection on the local machine, let alone from a remote. I guess there is some restriction somewhere but I gave up after half-an-hour of looking.

The reason I put the time in is that (if my memory serves me correctly) dovecot's solution is smart IMO. It allows plain-text from local but requires secure from non-local. This means that squirrel can connect to dovecot using plain-text since they are both on the same machine, usually.

I wondered if Slackware's uw-imap solution was the same, but, as I said, I couldn't get a successful connection to test it. Sorry I couldn't help.

Yes, Slackware builds with SSLTYPE=unix which provides very Dovecot-like behaviour as you described. So if you're building uw-imap from source, maybe try using that flag and see if it makes a difference with respect to plaintext logins over local connections.

That's OK, this is really more a matter of sheer curiosity than anything else :-)