Walt, that was abit harsh :)
Ruth, he is still right though, this is abit off topic for us, or any other
forum. When programming a new client or server implementing SMTP, there is
only one place to look, and that is in the documents RFC 821 and RFC 2821 as
published by the IETF. These documents specify (in 821) the original SMTP
standards, and (in 2821), the updated SMTP standard.
When writing a client, you must conform exactly to the requirements set out
in these documents, failure to do so will result in some clients or servers
not being able to interoperate with yours. These documents supercede all
tips, pointers and basic tutorials. I would especially recommend that you
distrust any tutorial from Microsoft (no offence to MS) that might have come
with your VB course, as MS Exchange is known not to conform to RFC 821, and
for directly violating RFC 2821.
The underscore issue is one of many violations regularly causing many
servers to drop any mail coming from an MS Exchange server that has been
misconfigured to send underscores in its HELO or EHLO statement. Underscores
are not allowed in DNS names, but may exist in NETBIOS names. Exchange uses
the machine's NETBIOS name by default, and thus sends underscores. RFC 821
and 2821 explicitly forbid this, and RFC 2821 even specifically requires
machines receiving underscores in a HELO or EHLO statement to deny the mail.
Here is one tip if you do want one.... Do not ever let your SMTP client send
an underscore in its HELO or EHLO statement.
These two RFCs specify the SMTP protocol standard in its entirity, and
following them strictly will insure you produce a client that can
interoperate cleanly with other servers and clients.
The documents are text files formatted for printing, and can be read at:
http://www.ietf.org/rfc/rfc821.txt
http://www.ietf.org/rfc/rfc2821.txt
If you prefer HTML versions, "unofficial" HTML versions of these documents
are available at:
http://www.faqs.org/rfcs/rfc821.html
http://www.faqs.org/rfcs/rfc2821.html
FAQs.org also carry copies of the original plaintext format RFCs, and PDF
formatted RFCs, if you prefer.
As a final side comment.... Stay away from VB.NET, it will melt your brain.
:)
Will
----- Original Message -----
From: "Walt Reed" <exim@???>
To: "Ruth Ivimey-Cook" <ruth.ivimey-cook@???>
Cc: <exim-users@???>
Sent: Saturday, November 22, 2003 6:10 PM
Subject: Re: [Exim] Help writing simple smtp sender
> This is not the correct forum to ask this type of question. It has
> NOTHING to do with exim.
>
> A newsgroup like comp.mail.misc may be a better alternative.
>
> On Sat, Nov 22, 2003 at 11:32:36AM +0000, Ruth Ivimey-Cook said:
> > Folks,
> >
> > At work I'm using VB.NET to write a class that can send a mail message
> > to an SMTP server, and do it properly. The reason is because I'm
> > learning VB and most of the alternatives cost money, and/or didn't have
> > the flexibility I wanted (e.g. logging the transaction). Note I'm not
> > asking here for info about VB, just about SMTP "clients".
> >
> > I know a reasonable amount about SMTP, and I'm not going to get
> > esoteric, but I did wonder if there are any 'tips' any of you have,
> > particularly in what to avoid or ways to approach the task.
> >
> > Regards,
> >
> > Ruth
> >
> >
> >
> > --
> >
> > ## List details at http://www.exim.org/mailman/listinfo/exim-users Exim
> > details at http://www.exim.org/ ##
>
> --
>
> ## List details at http://www.exim.org/mailman/listinfo/exim-users Exim
details at
http://www.exim.org/ ##
>
>
>
