Looking for a guide to collect all e-mail from the ISP mail server

[R. Diez]

>> Besides, the way you suggest means opening a SMTP port to the outside
> world. A security risk and more work at the firewall etc.
> 
> You can just allow some ip addresses of your provider to connect, not?
> Nothing outside world.


Yes, you all want me to open ports. I'm sorry guys, but I won't budge:

1) Opening a port means reconfiguring the firewall. You may find it funny, but some non-profits have no firewall, just a standard ADSL router. The 
ones that the telecom company provides often has no IP filtering abilities.

2) I will not expose an SMTP server to the outside word. I will not install in, or advise to, a small business a piece of software that craves for 
attention (patch me, patch me!).

3) Of course I can ask the current ISP. And they may comply. But how about the next one?

4) Of course I can filter my provider's IP in some Linux firewall. But then the provider will change its setup and won't tell me. Or I will not have 
time to modify the configuration. Or the next person will not have time just this week.

5) There is really no need. A multidrop / "catch all" mailbox should work fine. And it is a pretty standard feature in all ISPs I know of. Many people 
are using this kind of setup.

It's only that it is hard to learn, because there is no single, complete tutorial for this kind setup that I have found yet. But I am collecting more 
info, so maybe I will end up writing one myself.

6) Even if it does not make sense, I want to learn how to do it. Just for fun.

You probably mean it well, but if that is all the advice you can give me, it is not really helping!

I really still think that you should not advise other people to expose servers on the Internet if there is not really a _very_ good reason, especially 
for small businesses or volunteer-driven clubs or charities. The only good reasons I found yet are for SSH and OpenVPN. Anything else is a "no go" in 
this kind of environment.

Regards,
   rdiez