Am Donnerstag, 24. Oktober 2002 08:46 schrieb Ed White:
> Hi,
>
> I got this idea:
> automagically use the MX SMTP to deliver mail.
>
> What does it means ?
[snip]
> We can speedup things and void local SMTP adding the option to connect
> _directly_ to the destination SMTP.
>
> Example:
>
> From: me@myself.com
> To:=09you@yourself.com
>
> When you click "send", KMail looks for the MX record via DNS for the "T=
o"
> domain.
> MX:=091.2.3.4
> Now the KMail connects to that SMTP and relay your mails using classic
> "commands".
>
>
> What about ? ;-)
>
> =09Ed
>
> P.S. I read somewhere on the net that there's a Win client that already=
 do
> this, but I couldn't find it.
Hi Ed,

I see two problems with this approach, the first of which can be solved, =
the=20
second cannot:

1) There's a little bit more to direct sending than just look for an MX r=
ecord=20
and send to that server. You'd have to check for all MX records, take int=
o=20
acount their priority and try them according to this list until you found=
 a=20
working server. (which basically means duplicating code that already exis=
ts=20
in any MTA)

2) This is the real showstopper - many sites use MAPS DUL or similar=20
blacklists to disallow dialup clients to send directly to their mail=20
exchanger in order to reduce SPAM. This is because spammers often send=20
directly from their dialup lines to avoid problems with abusing their ISP=
s=20
MTA or having to look for open relays.

Once upon a time I had my local sendmail configured to send mail directly=
 to=20
the recipient's mail exchanger but noticed very soon that this was a bad =
idea=20
because many messages were returned because I'm on a line listed in DUL. =
I've=20
been using my ISPs MTA as smarthost since.

Just my 2e-2=E2=82=AC
-Malte

PS: there's another reason to use a local *) MTA: it's usually faster to =
pump=20
a message to a host on your LAN or to your ISP than to some MX on the oth=
er=20
side of the globe.

*) either really local or at your ISP's

_______________________________________________
KMail Developers mailing list
kmail@mail.kde.org
http://mail.kde.org/mailman/listinfo/kmail