[wplug] sendmail curiosity

[bpmedley at 4321.tv]

On 22 Aug 2001, Doug Green wrote:

> I think I mean (?) setting up sendmail itself. In order to use things
> like pine and mutt I need to have sendmail and fetchmail configured.
> However, other mail programs (evolution, balsa, etc.) just need to be
> pointed to an SMTP server and they work. So my question is: if I use
> sendmail with something like pine, do I no longer need to use the smtp
> server of my ISP? The man pages of sendmail state that it "...sends
> messages to one or more recipients, routing the message over whatever
> networks are necessary." So, can I assume that means that all mail
> routing is being done by my local machine (ie: no need to use an smtp
> server)? Thanks in advance for the help!

I don't understand.

You mention sendmail + fetchmail, but you also mention SMTP.  I was under
the impression that:
    sendmail + fetchmail == retrieving mail
    SMTP == sending mail

Which are you trying todo?  Both?

Oh well, I'll just type a few random responses, anyway..;)

Sending:

Pine does not need sendmail to, umm, send mail (sic).  However, it can use
sendmail if you want to.  Why would you want that?  One reason is so you
can send mail w/ a username that is not valid for your ISP.  This is handy
if you have multiple email accounts.  For example, one provided by your ISP
and another provided by a free (or pay) service.  Many people do this so that
they can subscribe to lists and things with a *public* email address.  Then
their friends and whatnot can send them stuff with a *private* email
address.  This allows for aggressive spam filtering on the public email
address while minimizing the possibility of losing a valid email.

Pine will work with sendmail with at least these two scenarios:

    - running as a daemon
    - not running as a daemon

The first is accomplished by starting sendmail and telling pine to connect
to 'localhost'.

The second is accomplished by leaving the SMTP server field blank.  Pine
will launch sendmail on demand.

Note, however, that you don't need sendmail at all.  You can specify the
SMTP server for your ISP in Pine's configuration options.

Receiving:

Many people use fetchmail to retrieve mail for them.  By default, this
program will dump the mail to the system's mail transfer agent (MTA) (by
connecting to port 25, etc).  It is then upto the MTA to deliver the mail
to the correct user.  Said another way: fetchmail will get it from your
ISP, and the MTA will get it to your mailbox.  As in:

    ISP => fetchmail => MTA => user's mailbox

In the above example sendmail could act as the MTA.  So, "fetchmail +
sendmail" could be written as:

    ISP => fetchmail => sendmail => user's mailbox

However, I've read that you don't need to actually run an MTA.  That is,
fetchmail can deliver to an arbitrary program.  However, you will need to
deliver to a program that is sufficiently intelligent to make sure that the
mail will get to the user's mailbox.  procmail is one such program that is
sufficiently intelligent.  procmail stands for process mail.  It can do
really neat things with your mail.

So, you can run "fetchmail + sendmail" or "fetchmail + procmail".  (As an
aside, you can also run "fetchmail + sendmail + procmail").

One reason to do this is so you don't have to run sendmail as a daemon.
AFAIK, daemon mode is required for getting fetchmail + sendmail to work.  A
good reason for not running sendmail all the time is that it has numerous
security flaws floating around.  These flaws get fixed, but it's a burden
on the user to keep track of all bugs/versions/workarounds for bugs not
fixed, etc.

Does this help any?

Also, this was all from memory, so there are undoubtedly errors.  Please,
if you see one, send a correction.

> On 22 Aug 2001 20:29:31 -0400, James O'Kane wrote:
> > Could you give a little more context? Are you asking about setting up
> > sendmail or setting up a client to use the locally installed sendmail?

~'`^`'~=-.,__,.-=~'`^`'~=-.,__,.-=~'`^`'~=-., \|/  (___)  \|/ _,.-=~'`^`
                          Brian Medley         @~./'O o`\.~@
"Knowledge is Power" brian.medley at verizon.net /__( \___/ )__\  *PPPFFBT!*
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