Re: MTA: usage of smart host

[David Fokkema <fokkema@nat.vu.nl>]

> | > > Thank you for all your suggestions and even config-files! It looks like
> | > > I'm able to go without my ISP's smart host. I was able to telnet into
> | > > ursine 25, although it knocks on my firewall port 113 (auth). Why is it
> | > > doing that? Right now, my firewall blocks this port and it reeeeeally
> | > > slows down transaction.
>
> Change the rule from "DROP" to "REJECT".  Then you won't be waiting
> for the other side to timeout.

Ah, looks like I have to move 'looking through my firewall code' up my
list. Of course, this works perfectly, :-). <shame>

> | > > But, what's all that about DUL and things like that?
> | >
> | > DUL, dialup list.  A list of all known dialup IP pools, frequently
> | > abused by spammers.
> |
> | Ah, I see. For what purpose is such a list available?
>
> As Paul said, those IP addresses are frequently used by spammers to
> send mail directly to you.  No other dial-up host would use a mail
> server, because by the very nature (and market) of dial-up it isn't
> suitable for servers.  Therefore, if you know which IPs will never
> have a vaild mail server you can simply not accept mail from them.
> That reduces the spam you receive on your mail server.

Got it, :-)!

> | > > Why is there something like a smart host?
>
> So that not every single machine that ever connects to the internet
> needs a permanent connection and a complete mail delivery setup.  One
> example is the typical Windows machine -- the "average" user dial up
> to their ISP and expects the mail will "immediately" get to the
> destination.  What really happens is their software passes all mail to
> the ISPs "smart" host (so-called because it is smarter than the other
> dumb hosts) which will then figure out how it should really be
> delivered.  Two other main reasons for smarthosts are mobile users
> with laptops, or a large UNIX network.  In both of those situations
> you keep the configuration on all the machines really simple and then
> use the smarthost for the real work.

Thanks!

David