1. 2009
    Jul
    20

    Switching to Google Apps

    Posted by David Zaslavsky on

    This weekend I switched over from Postfix to Google Apps (standard edition) to handle @ellipsix.net email addresses. Very quick and easy, yay :-)

    Why’d I do it? Not for any particularly weighty reason — Postfix was doing just fine as an SMTP server. I just thought it’d be nicer to have a separate account for mail that comes through the website, and all Postfix could do was forward emails to my regular Gmail account — unless I were to set up an IMAP or POP server of my own, and even then I’d miss out on Gmail’s nifty UI.

    Plus, there is one feature I really like about Gmail that I haven’t seen in any other webmail system. Messages that I send from my laptop or phone through Gmail’s SMTP server show up as sent messages when I log in online. It’s tremendously useful not to be missing half of a conversation when I want to send emails from a public computer.

  2. 2009
    Feb
    10

    Greylisting really works

    Posted by David Zaslavsky on

    There are a lot of programs and protocols out there devoted to stopping, or at least reducing, the flow of spam email around the internet. But one of the most effective is also one of the simplest: greylisting.

    In order to understand greylisting, you first need to know that a typical email message on its way through the internet travels through four computers (“nodes”):

    1. The origin client (often a personal computer running a MUA - mail user agent - like Thunderbird, Outlook, Evolution, etc.)
    2. The relaying server (this server would be named in the configuration of Thunderbird, Outlook, Evolution, etc. as the SMTP server)
    3. The destination server (for mail sent to user@example.com, this is the email server for example.com)
    4. The receiving client (often another personal computer running another MUA)

    Greylisting is actually a simple process: the first time node 2 tries to send the email to node 3, node 3 responds with an SMTP 450 error code, which basically means “try again later”. And a standards-compliant mail server will indeed try again later. But a spammer’s server usually won’t. Spammers typically operate their own mail servers which are specially designed to send out as many emails as …