IIS and SMTP - Smart Host setting ignored

Author

Smart Host setting ignored

Eric Dawes

2004-11-04, 5:50 pm

1. Using CDONTS in ASP scripts to send mail. Want to target a specific smart
host.
2. Have set the Virtual SMTP / Delivery / Advanced / Smart Host
3. Have gone to IIS settings on domain and set "Server Extension" and Mail
host
....but messages still go through a "default" pickup queue instead of the
intended server.

(4. I also tried CDOSYS where you can specify the SMTP server ... script
confirms the setting I want but the message header still shows "default" mail
host instead of intended one).

Am I missing a setting? This behavior on both a DSL-connected Win2K and on
a Win2K within the ISP's colocate cage. Both boxes can telnet/ping the
intended server, so this feels like a routing issue.

Thank you in advance for ideas/advice!

Ken Schaefer

2004-11-07, 2:47 am

You misunderstand what a smarthost is in the context of MS SMTP server
settings.

The Smarthost setting in MS SMTP server means that all mail that the MS SMTP
server has for sending out to remote servers will instead be delivered to
the smart host instead of being directly delivered to the MX host in the
remote domain's DNS information.

Now, when the smart host receives the mail, it's going to add a set of SMTP
headers (Received from <MS SMTP server> (IP address) at <date/time> for
<somewhere> )

OK, now let's deal with the other stuff:
CDONTS doesn't use TCP sockets to deliver mail. All it does is create a
correctly formatted text file, and saves this into the MS SMTP server's
"pickup" directory. You can use CDONTS to directly connect to the MS SMTP
server's listening port (port 25) nor can you use it connect directly to a
remote SMTP server's listening port. All it can do is create the appropriate
text file and save it directly onto the server's hard disk, where MS SMTP
server is configured to look for dropped files.

CDOSYS on the other hand can use sockets to connect to any SMTP server. So,
in your ASP code, you can specify the server that you've currently
configured as a smart host, so that CDOSYS directly communicates with that
server rather than the local MS SMTP server. In this case, it's similar to
an email client like Outlook connecting to an email server. The remote mail
server is *still* going to record that mail originated on your server
running CDOSYS.

Cheers
Ken

"Eric Dawes" <Eric Dawes@discussions.microsoft.com> wrote in message
news:E5F136BD-16C3-4DD2-8B4A-045EB002B7E2@microsoft.com...
> 1. Using CDONTS in ASP scripts to send mail. Want to target a specific
> smart
> host.
> 2. Have set the Virtual SMTP / Delivery / Advanced / Smart Host
> 3. Have gone to IIS settings on domain and set "Server Extension" and Mail
> host
> ...but messages still go through a "default" pickup queue instead of the
> intended server.
>
> (4. I also tried CDOSYS where you can specify the SMTP server ... script
> confirms the setting I want but the message header still shows "default"
> mail
> host instead of intended one).
>
> Am I missing a setting? This behavior on both a DSL-connected Win2K and
> on
> a Win2K within the ISP's colocate cage. Both boxes can telnet/ping the
> intended server, so this feels like a routing issue.
>
> Thank you in advance for ideas/advice!

Eric Dawes

2004-11-07, 5:48 pm

Thank you, Ken!

I am trying to route to the "smart host"; but every message seems to come
from the default mail server instead. Issue is with large campaigns, the ISP
wants me to use a server they have dedicated for my outbound.

But with the virtual SMTP pointing to intended smart host AND with "Server
Extensions" settings also routing to the intended smart host, the message
headers indicate they are being picked up by the default (MX) mail server and
not the smart host server (the "received: from ..." header has no reference
to my smart host server).

I am after the functionality you described in your first explanation ... to
have servers send to a specific box from my pickup queues. For whatever
reason, that routing doesn't feel like it's going on!!

If you have any other thoughts ... I'm all for 'em!!!!!

Thanks once again!
Eric

Eric Dawes

2004-11-13, 5:48 pm

Just in case anyone is using this thread to research a similar issue...here
is what I found (closure on the issue):

Once I put the I.P. address in the "Smart Host" settings (note the syntax of
[xxx.xxx.xxx.xxx] is recommended as the brackets improve lookup) I was
golden. I still do not know why name lookup of smart host was overridden and
numeric IP address is NOT, but in any case it solved my problem and may solve
yours' too!