validate email addresses?

[jaja714]

When I compose an email in Outlook, "somehow" the email address is validated against our company's server and becomes a hyperlink.  The email addresses that aren't valid become enclosed in quotes.  This is one way for me validate whether or not an email address is still valid.

On a broader scale, is there a way to "ping" some service out there to see if an email address is valid?  In other words, I can determine the server name from whatever is right of the "@" sign and then "ping" that smtp server to see if the email address is valid or not.

Is this doable?

[iamtheky]

check the AD UDF.   Has the ListExchange stuff that may be useful, maybe not, just sounds useful.

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[water]

With the OutlookEX UDF you can validate a mail address by checking against all accessed address books and distribution lists.

You can't validate an external SMTP address.

At least I do not know of a way to easily check if the specified domain exists.

[jaja714]

I suppose such a utility would be too useful for spammers!

[jchd]

Such a "tool" already exists: RFC2821

The RCPT or VRFY command or an empty DATA section will do in many servers.