Re: IdSMTPRelay not working in some locations

Giganews Newsgroups
Subject: Re: IdSMTPRelay not working in some locations
Posted by:  Remy Lebeau (re…
Date: Wed, 11 Jul 2012

Frank wrote:

> Then, however, I installed it at another user's location (my biggest
> customer of course), and it does not work. When this user attempts to
> send email to me, he says that my application reports success, but I
> never get the email.

Than it is likely an issue with your SMTP server itself, not with TIdSMTPRelay.

> The only thing I know that is different about this customer from all
> the others is he uses MS Exchange for email, whereas the others use
> POP3.

Makes no difference to TIdSMTPRelay.  It looks up the MX records of each
recipient's email address and then establishes a connection to each receiving
SMTP server directly.

> My understanding is that this should not matter as IdSMTPRelay
> avoids the use of the user's email server altogether.


> I'm currently in the dark as to what is short-circuiting this. Is
> there something I can do to troubleshoot this situation?

Use Wireshark or another packet sniffer to verify that TIdSMTPRelay is actually
connecting to your SMTP server and communicating with it correctly, that
the server is not reporting any errors to SMTP commands which TIdSMTPRelay
(or your code) may be ignoring.

> Is there any further information needed about my application and/or my
> implementation of IdSMTPRelay?

The only value that TIdSMTPRelay requires you to provide for it to work is
the TIdSMTPRelay.DNSServer property value.  Everything else is handled internally.
Are you providing a DNSServer that is accessible from the customer's computer?

Remy Lebeau (Indy Team)


In response to

IdSMTPRelay not working in some locations posted by Frank Marousek on Wed, 11 Jul 2012