pine and sendmail

[Geoff Shang]

On Wed, 21 Mar 2001, Terry D. Cudney wrote:

> 	Here's my question to the gurus: Is this "kosher"? A couple of
> times, the ISP rejected an outgoing mail with an error message about
> invalid domain or something (Can't remember exactly what it was). IS my
> ISP being lenient in allowing it most all the time?  or is it legal to
> do things this way?

I think your ISP is being lenient by letting it work most of the time.
What normally happens is that your local machine name and local domain are
included in headers such as sender.  Mail transporters will often look at
this and do a lookup to see who you are, and reject mail since as far as
it's concerned, a bounce would be undeliverable.  Many listserver programs
look at this too, at least for subscription, so it's worth fixing.

I run exim too so I can tell you how to fix it there.  The last section is
the address rewriting configuration section.  In it, you need to place an
entry like this:

<local address> <e-mail address> <flags>

The first field is the address on your system.  the second address is the
address you want the first address to have.  The flags I don't really know
about, and should probably look up someday.  Here is the entry I use:

geoff at data.home gshang at uq.net.au frF

Note that you don't need the same as your from address in your exim.conf,
you just need a valid address.  This means that I can send mail out as,
say, geoff at braille.uwo.ca, and my ISP will accept it because
gshang at uq.net.au is in my headers, hence it's uq.net mail.  The whole
reason for rejecting mail is to stop people using mail servers as spam
relays.

However, as I said before, some list server software require you to at
least have the right headers for subscribe and unsubscribe requests, and
perhaps for all mail.  So if I want to subscribe to a list as
geoff at braille.uwo.ca, I would have to temporarily (at least) change my
rewriting rule to use this address instead.

There is an example in my /etc/exim.conf of how to use another file with
address info for user accounts, but it doesn't document the file format
there (it might elsewhere).

Geoff.