Re: RegularExpressionValidator and fake email addresses

You can't.  You can use regex to make sure the email address is
formatted properly, but to be 100% sure it's a valid address, you need
to send an email and see if it bounces.

You could get tricky and check the domain's MX record to see what server
is handling mail for the domain.  And then try and connect on port 25
(which may not be open or it may be running on a different port) and
then see if the mail server supports "RCPT TO" (which it may not) and
then hope that RCPT TO provides meaningful response (it might always
return an "invalid" response to prevent spammers from pre-checking an
email address before they send out their bulk crap).

---
Patrick Steele
http://weblogs.asp.net/psteele


-----Original Message-----
From: Discussion of building .NET applications targeted for the Web
[mailto:[email protected]] On Behalf Of James Hearne
Sent: Thursday, May 24, 2007 10:34 AM
To: [email protected]
Subject: Re: [DOTNET-WEB] RegularExpressionValidator and fake email
addresses


No, this isn't applicable. I don't want to send out any email. I just
want to check if the provided email address does exist or not. How can I
do that?

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