branch14log

At my company we usually host Rails projects on Debian. Exim has been Debian's default MTA for quite some time so we stick with it. But recently I've run into some troubles while upgrading a Rails 2 application to Rails 3. With ActionMailer.delivery_method = :sendmail Rails resorts to sendmail executable in its path to send emails. And while Sendmail is quite happy with the default options (-i -t) used by Rails, the sendmail replacement provided by Exim isn't. Exim's sendmail behaves differently with option -t than Sendmail. That's why I had to put the following in config/environments/production.rb file to make it work. ActionMailer::Base.sendmail_settings[:arguments] = '-i' Before that I got the following error message via email

A message that you sent using the -t command line option contained no
addresses that were not also on the command line, and were therefore
suppressed. This left no recipient addresses, and so no delivery could
be attempted.

But as always man exim has all the nitty gritty details. Here is the fine print:

-t        When Exim is receiving a locally-generated, non-SMTP message on  its  standard  input,
          the  -t  option causes the recipients of the message to be obtained from the To:, Cc:,
          and Bcc: header lines in the message  instead  of  from  the  command  arguments.  The
          addresses  are extracted before any rewriting takes place and the Bcc: header line, if
          present, is then removed.

          If the command has any arguments, they specify addresses to which the message  is  not
          to  be delivered. That is, the argument addresses are removed from the recipients list
          obtained from the headers. This is compatible with Smail 3 and in accordance with  the
          documented  behaviour  of several versions of Sendmail, as described in man pages on a
          number of operating systems (e.g.  Solaris 8, IRIX 6.5, HP-UX 11). However, some  ver‐
          sions  of  Sendmail add argument addresses to those obtained from the headers, and the
          O'Reilly Sendmail book documents it that  way.  Exim  can  be  made  to  add  argument
          addresses     instead     of     subtracting    them    by    setting    the    option
          extract_addresses_remove_arguments false.

          If there are any Resent- header lines in the message, Exim  extracts  recipients  from
          all Resent-To:, Resent-Cc:, and Resent-Bcc: header lines instead of from To:, Cc:, and
          Bcc:. This is for compatibility with Sendmail and other MTAs. (Prior to release  4.20,
          Exim gave an error if -t was used in conjunction with Resent- header lines.)

          RFC  2822  talks  about  different sets of Resent- header lines (for when a message is
          resent several times). The RFC also specifies that they should be added at  the  front
          of the message, and separated by Received: lines. It is not at all clear how -t should
          operate in the present of multiple sets, nor indeed exactly what constitutes a  "set".
          In  practice,  it  seems  that MUAs do not follow the RFC. The Resent- lines are often
          added at the end of the header, and if a message is resent more than once, it is  com‐
          mon  for the original set of Resent- headers to be renamed as X-Resent- when a new set
          is added. This removes any possible ambiguity.