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View Full Version : validating actual e mail addresses


edbr
11-26-2008, 03:36 AM
a while ago in a post someone asked if an email address could be validated to see if it exists, i knew i had seen it on a site but lost the link.
I just found this http://www.rolosoft.com/software/email-check/wa/lite/validate.aspx any one got a clue how this works?
I tested it with yahoo, hotmail and gmail and they all work

davidj
11-26-2008, 06:23 PM
you cant validate an email address other than check formating

when a user keys an email address into a form you can send an email to that address. The user has to click a link to confirm the address is their own and then finalise the registration process

davidj
11-26-2008, 06:30 PM
additional...

i have checked the link and this email address is valid

s@eaga.com

I work for eaga but i know there is no one called 's' so does this mean the address is valid (in the correct format)

domedia
11-26-2008, 06:37 PM
Of course it can't check for real. It will make an educated guess based on the response from the mail server.

edbr
11-26-2008, 11:47 PM
i think its more than that David and Dom.
if i tried ed_br or edbr at yahoo gmail and hotmail it correctly identified where i have an account or not
i have edbr at hotmail and gmail but ed_br at yahoo

I yahoogled and i think it works on yahoo gmail etc as if you send to a faulty account on these you get a message , no such account, and its suggested it somehow it utilises that.
i didnt try a pop3 ,but often servers have a catch all account so a malformed address will not get a response in that case
I came accross another site doing the same but it came back with a lot of info on the server to. both where aspx pages . Jut very curious how its done

domedia
11-27-2008, 12:25 AM
I tested on a domain I own, and it comes back with 'valid' no matter what I type in. The script is not allowed to check for actual accounts (think about the security issues that would create), but it can ask the server if an account exist. If a server has a catch-all setting, there is never going to be a 'no such email account' response :) The server might not be telling the truth.. Some email servers just trashes the request for email account if it does not exist.. you won't even get a bounce back.
It all depends on how the mail server for the domain of the email account you're checking is set up. Your observation Ed is correct, some server will send a message if there is no such (or there is such a) account, others are just configured different.

edbr
11-27-2008, 12:53 AM
found this article which opens an answer up more maybe
http://www.codeproject.com/KB/validation/Valid_Email_Addresses.aspx
seems it is possible to a degree but is certainly not perfect .

domedia
11-28-2008, 03:49 AM
We validate using a couple of those methods. First simply the syntax and secondly a handshake with the mail server. Again, the mail server can be set up to respond to this request in several ways.

edbr
11-28-2008, 04:07 AM
my interest is in the free mail group i guess, most mails from pop3 addresses are usually correct i quite a few applications with incorrect e mail addresses, on purpose and otherwise. which is frustrating. not sure if i will use this or not though.
I also read that these handshakes could get you marked as spammers but cant see that.
i only get around 50 - 100 form submissions a day so i might just put this on the backburner.