On 2009-02-15_13:13:09, Brandon Sandrowicz wrote: > On Sun, Feb 15, 2009 at 06:41:46PM +0000, James Freer wrote: ...snip...
> Exim is part of the default install because in the olden days all of > your email was delivered to the 'mail spool' (usually > /var/mail/$USERNAME or /var/spool/mail/$USERNAME) and you read it from > there, possibly copying it to a local home directory (like ~/Mail/inbox > or something similar). Lots of command-line and backend programs relied > on this functionality, and sent things like error messages to your mail > spool. Many still do. For example, if you define a process to run in a > schedule on > cron, any output (either to STDOUT or STDERR) will be packaged into an > email an sent to your mailspool (the assumption being that any output > that isn't going to a log file is an error that you'll want to know > about). Even today an MTA is needed for hosts that have special uses. Firewalls, etc. On these machines there are a bunch of daemon processes, which can get into trouble, and need to be able to call for help. On Debian, and likely othe distributions, this is done by sending local email to root. The sysadmin is supposed to look at this spool periodically. Without an automatic install of a MTA, this idea would be already broken out of the box. Debian has choosen Exim/Exim4 for this function in the base system. If you install some other MTA or intend to rely on your MUA for MTA services, you may not be able to remove the MTA that the distribution provided, unless you make sure that your substitute is actually handling this 'hidden' email traffic. There are daemons on your computer that may, some day, need to talk to you. -- Paul E Condon pecon...@mesanetworks.net