RE: Editing E-Mail Addresses

On Mon, 2006-02-13 at 13:22 -0500, Fisher, Don wrote:
> Thanks, Rich.  I think that cleared up my confusion.  The MX records are
> like routing steps for a domain.  For example, IBM.com has 10 MX records.
> According to the document, if I send a message to "somebody@xxxxxxx", the
> e-mail server (SMTP) will attempt to use each of those MX idenfitiers in
> priority order to reach the addressee.  
> 
> Therefore, it appears the steps really look like this:
> Check for MX records.
> 
> If any exist, the domain is okay.  
Probably ok from a 'verify the syntax' approach.  Since mx records are
just a pointer to a server, there is no guarantee that any of the listed
machines will answer on port 21, or that they would deliver mail to the
intended recipient.

Keep in mind also that DNS servers can fail.  If there is any sort of
routing problem in the internet, you might not receive a response, so
you may want to consider treating a failure as a warning.

> If there are no MX records, use GetHostByName to determine if the domain is
> okay.
> 
> Or am I still lost?
> 
> Thanks.
I think this would be okay.


Really, there is no "correct" or 100% solution to this problem, given
the architect of the internet, unless you actually get the user to
respond to an e-mail that you sent them.  So, if you judge the code to
be good enough, then it probably is.

Regards,
Rich