Autor: Tim Jackson Fecha: A: exim-users Asunto: Re: [exim] Users wanting to send mail from a dial-up (ISP) connection
On 25 Nov 2004, Robert Cates wrote:
> Simply put, I would like to know how to configure Exim (4.32) to allow a
> user to send e-mail when he/she accesses by way of a dial-up connection
> (e.g. from home), using e.g. Outlook Express.
You need to use SMTP AUTH. That is, provide an authentication mechanism
(typically username/password) which is given to the user and which they
enter in their mail client for use when *sending* mail.
Chapter 33 in the Exim manual covers this topic. Exim does not come
configured by default to perform SMTP AUTH, mainly because the
authentication mechanisms in use vary from system to system (you can
authenticate against pretty much anything from a plain text file to MySQL,
LDAP etc.)
> I'm having a hard time understanding this because I thought Exim checks
> the From/Sender e-mail address (which would be of course
> user@???) and will then attempt to send the mail.(?)
No. This would not be sensible, because it would turn your server into an
open relay. For example, a spammer could send an email apparently "from"
one of your users and your server would relay it. You can configure Exim
to do that, but please don't.
> Would I have to specifically allow Exim to relay from the ISP the user
> is connecting from?
You can only do this if you have trusted users with fixed IP addresses.
Even then, it's rarely a good idea because increasingly people want to be
able to roam around with laptops etc. Much better just to solve the
problem permanently by making everyone use SMTP AUTH - then, they can send
mail from anywhere, independent of IP or ISP etc.
