How to validate an email address

[steve.milner]

Do you speak SMTP?

Get the MX record for the_domain.com for example smtp.the_domain.com

then from a bash prompt type:
telnet smtp.the_domain.com 25
ehlo from_me.com
mail from:<me@123.456.com>
rcpt to:<someone@the_domain.com>

if you get a "user unknown" message here then that's an indication the mail doesn't exist

next type "quit"

And the connection will be broken, without any mail having been sent regardless.

Just an idea.

Steve

[moxquito]

Although this is a good idea in practice.. unless he is part of that domain this will not work. Most if not all ISP's deny a connection from an IP that is not part of their domain to prevent relaying, and anyone running a mail server would be retarded to not implement this feature

[jkaneda]

"Just for sake of completeness, you *could* verify the existence of email addresses using the VRFY and EXPN commands of the SMTP protocol (see RFC 2821).

Unfortunately, thanks to spammers, these commands are ignored or return an error on most servers, despite the fact that they would be quite useful in practice."

http://social.msdn.microsoft.com/For...-3af8ae06cec9/

[oofki]

You think spammers are the reason those commands are blocked, how so? I am interested in that...

I figured it would be more of a privacy thing but maybe that ties in to the whole spam theory as well?

[nihil]

I guess I am cynical, but I believe that people are more interested in their bandwidth than my privacy.

I assume that it would be advantageous to spammers to verify the existence of an e-mail address before sending anything to it?

[oofki]

I think you may be right about the bandwidth that was another thing I was thinking.

And I think it would be yes, because they could maintain their "distribution list" of victims...

[Negative]

I doubt that any spammers would go through the trouble of verifying email addresses before spamming them. I sometimes send out more than 200,000 emails on a single day (from one server with a decent pipe); all I do is keep track of the returned ones so that I don't hit those anymore next time. But verifying their existence before sending? Just an extra step that doesn't really help me out...

[nihil]

Negative, really! I didn't know that you were a spammer

I sometimes send out more than 200,000 emails on a single day (from one server with a decent pipe); all I do is keep track of the returned ones so that I don't hit those anymore next time.

Correct me if I am wrong, but don't spammers use fake addresses, so they wouldn't get the feedback (and the Feds ).

I don't know much about the details, but I believe that there is quite a market for spamming lists. If you could sell them as verified I would guess that you could charge more for them? The basic difference between legitimate and illegitimate usage?

[Negative]

I play by the rules - most of them are customers

Correct me if I am wrong, but don't spammers use fake addresses, so they wouldn't get the feedback (and the Feds ).

I don't know what spammers do - I was talking about what I do, not about what spammers do

[Cheap Scotch Ron]

I sometimes send out more than 200,000 emails on a single day (from one server with a decent pipe);

don't know what spammers do - I was talking about what I do, not about what spammers do

Oh sure.