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how to find out if an e-mail address exists?

  • 09-05-2005 11:56pm
    #1
    Closed Accounts Posts: 583 ✭✭✭


    i need to send a few e-mails to people i know that there e-mail address is of the form forename.surname.X@domain.com where x is a number. is there anyway that i can "ping" for want of a better word, an e-mail address to see if it exists?


Comments

  • Closed Accounts Posts: 154 ✭✭smorton


    stuey wrote:
    i need to send a few e-mails to people i know that there e-mail address is of the form forename.surname.X@domain.com where x is a number. is there anyway that i can "ping" for want of a better word, an e-mail address to see if it exists?

    the following code:
    To:forename.surname.X@domain.com
    from:me@mysite.com
    subject:yoohoo. anybody there?
    :D

    not that i know of but if you send them an email and it doesn't exist you'll get an automatic email shortly afterwards saying that delivery failed. any good to you?


  • Registered Users, Registered Users 2 Posts: 4,093 ✭✭✭muckwarrior


    Yeah it's possible. You can do a reverse DNS MX record lookup. Can't remember exactly how offhand. Prob easier to just do it the way mentioed above.


  • Registered Users, Registered Users 2 Posts: 3,888 ✭✭✭cgarvey


    smorton's way is the only definitive way to test. If you don't want to be detected you can query the mail server directly, but a lot of mail servers are configured to accept mail point blank, and then deal with whether or not the user exists (after accepting the mail). The following test won't work in those cases, but if the mail server does a realtime user lookup, it will....
    nslookup -type=mx thedomain.com
    
    will give you something like
    thedomain.com  MX preference = 10, mail exchanger = mail.thedomain.com
    
    and you need the mail.thedomain.com bit.
    telnet mail.thedomain.com 25
    
    and you should get some sort of a response which will probably mention "220" and "SMTP", then type
    helo myowndomain
    mail from: mytestmail@mail.com
    rcpt to: theaddressiwanttotest@thedomain.com
    
    If you get "OK" after that then either the user exists, or the server is configured to accept all mail, and process it after the SMTP session. Type "quit" (and return) to get out of the session.

    .cg


  • Registered Users, Registered Users 2 Posts: 37,485 ✭✭✭✭Khannie


    cgarvey->setNetworkingGeekStatus(cgarvey->getNetworkingGeekStatus() + 1);

    ;)

    One suggestion on top of cgarveys: Turn on local echo in your favourite telnet client. Otherwise you'll be looking at a blank screen when typing your protocol bits.


  • Registered Users, Registered Users 2 Posts: 4,093 ✭✭✭muckwarrior


    cgarvey wrote:
    mail from: mytestmail@mail.com
    rcpt to: theaddressiwanttotest@thedomain.com
    
    If you get "OK" after that then either the user exists, or the server is configured to accept all mail, and process it after the SMTP session. Type "quit" (and return) to get out of the session.

    .cg
    AFAIK most servers will only validate the domain in the RCPT TO command before returning an OK. It won't check if the actual user exists.

    To check if a particular user exists on the server youshould use the VRFY (verify) command. e.g vrfy user@domain.com. Technically you could use a wildcard to return all users but most servers won't allow this.


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  • Registered Users, Registered Users 2 Posts: 10,984 ✭✭✭✭Lump


    smorton wrote:
    the following code:
    To:forename.surname.X@domain.com
    from:me@mysite.com
    subject:yoohoo. anybody there?
    :D

    not that i know of but if you send them an email and it doesn't exist you'll get an automatic email shortly afterwards saying that delivery failed. any good to you?

    That's what I'd do...

    John


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,126 Mod ✭✭✭✭Capt'n Midnight


    you can use MX records to verify that the bit after the @ symbol is valid

    as for the bit in front of the @ symbol - that is entirely down to the email server to validate, and if it's configured to block replies or not, some are.

    If you had an email server that dialed up you could have a situation where your email was delivered to the ISP's mail server (do you get a delivery reciept from it ??) and not picked up by the real server till later. That server may not send a non-delivery back for several days if at all.

    There used to be stuff like FINGER - but privacy concerns and the insiduous nature of SPAM mean they no longer work and that most organisations don't hand out mailing lists willy nilly.


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