checking email validity

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checking email validity

Fiorenzo de Palma
Hi,

we'd like to check wether an email address is correct or not.
By correct I mean:
- does the mail server exist?
- does the user exists in this mail server?
- this user mailbox is OK to receive emails?

I know that we can check the MX via the DNS tags, but is there a way  
to ask a SMTP server information about a specific user?
We need that in a subscription page and as we have very often typos  
or "funny" email addresses, we want to check that address ASAP when  
the form is submitted.

Thanks


Fiorenzo de Palma
Direction

http://www.mediancer.com
____________________
Mediancer Sàrl
Joliette 5
CH-1006 LAUSANNE
Tél. 021 / 617 07 07








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Re: checking email validity

Jolle Carlestam
If I had an SMTP server with that feature I would turn it of  
immediately. I shiver thinking of what a Spammer could do with that.

My approach is to send a confirmation mail to the address used and in  
that have some kind of confirmation code. The registration is not  
complete without entering that code.

You can also do a check for typos by having two email fields. If the  
don't match then there's a typo. And of course use valid_email to  
check that it's formally correct.

HDB
JC

25 jan 2007 kl. 11.35 skrev Fiorenzo de Palma:

> Hi,
>
> we'd like to check wether an email address is correct or not.
> By correct I mean:
> - does the mail server exist?
> - does the user exists in this mail server?
> - this user mailbox is OK to receive emails?
>
> I know that we can check the MX via the DNS tags, but is there a  
> way to ask a SMTP server information about a specific user?
> We need that in a subscription page and as we have very often typos  
> or "funny" email addresses, we want to check that address ASAP when  
> the form is submitted.
>
> Thanks
>
>
> Fiorenzo de Palma
> Direction
>
> http://www.mediancer.com
> ____________________
> Mediancer Sàrl
> Joliette 5
> CH-1006 LAUSANNE
> Tél. 021 / 617 07 07
>
>
>
>
>
>
>
>
> ============================================
> Attend the Lasso Summit
> March 2-4, 2007 in Fort Lauderdale, FL
> http://www.LassoSummit.com/
> ============================================
>
> ------------------------------
> Lasso Support: http://support.omnipilot.com/
> Search the list archives: http://www.listsearch.com/lassotalk.lasso
> Manage your list subscription: http://www.listsearch.com/ 
> lassotalk.lasso?manage


============================================
Attend the Lasso Summit
March 2-4, 2007 in Fort Lauderdale, FL
http://www.LassoSummit.com/
============================================

------------------------------
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Search the list archives: http://www.listsearch.com/lassotalk.lasso
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Re: checking email validity

Wade Maxfield
>If I had an SMTP server with that feature I would turn it of
>immediately. I shiver thinking of what a Spammer could do with that.
>
>My approach is to send a confirmation mail to the address used and
>in that have some kind of confirmation code. The registration is not
>complete without entering that code.
>
>You can also do a check for typos by having two email fields. If the
>don't match then there's a typo. And of course use valid_email to
>check that it's formally correct.
>
>HDB
>JC
>
>25 jan 2007 kl. 11.35 skrev Fiorenzo de Palma:
>
>>Hi,
>>
>>we'd like to check wether an email address is correct or not.
>>By correct I mean:
>>- does the mail server exist?
>>- does the user exists in this mail server?
>>- this user mailbox is OK to receive emails?
>>
>>I know that we can check the MX via the DNS tags, but is there a
>>way to ask a SMTP server information about a specific user?
>>We need that in a subscription page and as we have very often typos
>>or "funny" email addresses, we want to check that address ASAP when
>>the form is submitted.
>>
>>Thanks
>>
>>
>>Fiorenzo de Palma
>>Direction
>>

There is a SMTP VRFY command but some servers (maybe most) don't
allow it's use, for exactly the reasons JC mentioned.  I know in EIMS
there is an option to disable it.

You could try checking the MX using the DNS tags, then using the Net
tags open a telnet session to the server on port 25.  The results of
that would tell you if the mail server actually exists.

As far as checking the user, the best way is the old test message
with confirmation code/link as JC mentioned.  Anything else gets
pretty tricky (say sending a test message and checking the status of
it using lasso - there was mention of this a little while a go on the
list, so check out listsearch - the biggest issue here will be
keeping track of each individual email and it's status as they may be
in the queue for quite a while, with the increased use of greylisting
by many mail servers)

  - Wade

============================================
Attend the Lasso Summit
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