usendmail README -- 2001-02-06 -- Uwe Ohse <uwe@ohse.de>


usendmail is a replacement for the sendmail clone of the qmail package.


Nomenclatura:
* usendmail is usendmail
* qsendmail is the qmail sendmail clone
* sendmail is plain old sendmail (getroot)


Compared to sendmail qsendmail is:
* fast
* safe
* secure
Unfortunately qsendmail isn't completely bug-compatible to sendmail.


Reasons to use usendmail instead of qsendmail:

1) Sendmail parses addresses given on the command line in the
   same way it parses mail headers ("To:").
   The qmail sendmail clone doesn't do this. This is a problem is
   you, for example, run a http server for your customers which use
   their own broken cgi scripts and expect to be allowed to do all 
   kinds of wrong things, so usendmail behaves more like getroot.

2) Qsendmail doesn't know about a number of sendmail commandline
   options. Usendmail knows more of them (and handles them 
   through ignorance).

3) Qmail-inject, the backend of qsendmail and usendmail, expects
   a few environment variables to be set, otherwise it defaults
   to use anonymous@host.name as the default header or envelope
   from address.
   This is a problem is qsendmail is called by a cgi script without 
   any of these environment variables set. "anonymous@host.name"
   is possibly not the address the system administrator want's
   to see in that case.
   Usendmail works around that:
   * if the envelope is missing it tries to parse the Sender or
     From headers.
   * if Sender and From are missing, too, then usendmail sets
     $USER by looking up the user id it runs under in the systems
	 passwd.
   This is not a breach of privacy but the change of an 
   unwanted default.


Installation:

* make
* make install
* cd /usr/sbin ; rm sendmail ; ln -s /usr/local/bin/usendmail sendmail
  (replace sbin by lib, if needed)