When good ideas go bad

As many people know, I run a mail system for myself and a few other family members and friends. Up until this week it used a very robust backend being driven by Mac OSX and postfix, mailscanner, spamassassin and clamav. However, in my day job I've been gaining a lot of experience and respect for a bundled open source platform called Zimbra. So I thought I could kill two birds with a one nuke and drop Zimbra onto a new Linux-powered machine. In principle, this was (and still is) a good idea.

It provides me, as an administrator, a number of benefits such as:

  • Centralised user/account management
  • Extremely simple deployment of virtual domains etc
  • Intuitive web administration as well as a plethora of command line tools (so I can roll my own scripts for routine tasks etc)
  • Having everything in one place makes backup (and restore) a LOT simpler
  • Being a commercial product with an open-source alternative means I get the best of both worlds: an free product with a proactive vendor constantly developing and improving their product.

All these benefits mean I have more time to spend doing things that I enjoy and less time doing mundane stuff that I really hate. Also it gives me a real-life test environment with real-world mail feeds that I can experiement with before deploying anything on the production systems in my day job.

Of course, I'm not the only winner. Users of my system can now do all sorts of things they couldn't before. Such as:

  • Manage their own mail and account details in a single web interface.
  • Store mail on the server and have it filtered server-side.
  • A featureful web mail client with their own address book.
  • Ability to create RSS feeds for specific mail folders (or their entire mailbox) which opens up a whole new way to interact with the mail server.

There are other features as part of Zimbra such as secured (SSL/TLS) mail that were part of the old system too.

It is this last feature though that is causing me all the grief. Over the last 3 days, since deploying the new server, a single feature has failed miserably. Sending mail requires users to authenticate themselves so the system knows they are allowed to send mail through the server. Otherwise, the server would be an open mail relay which are the bane of the Internet and good way to get yourself onto so many block lists the server would be rendered useless within a day or two at the most. I'm busting a valve trying to fix this, but in the meantime, at least webmail works completely!!

Warning - serious geek tech follows :)

Despite all my efforts to get this one little feature working, all I've managed to do is eliminate a bunch of things that aren't causing the problem. Finally, it's come down to a rather complex interaction between four components: postfix -> saslauthd -> tomcat(via soap) -> ldap. In that chain, it appears the failure is in the interaction between postfix and saslauthd but getting any meaningful information out of the standard logging has proven to be difficult at best and utterly useless the rest of the time. Seems I am going to need to break out some big guns and start doing stack traces and library traces to see where this is falling down. In any case, this is several orders of magnitude more complex than it should be for a bundled product from a commercial vendor being installed onto a supported platform.

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