 testing email deliverability... [message #186037] |
Thu, 05 June 2014 00:48  |
The Natural Philosoph
Messages: 993
Registered: September 2010
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I have web contact pages which are used by anyone to send enquiries.
I want to make sure that anyone using them has a valid reply address set
in a web form BEFORE I forward the message on to the site administrators.
Mailer is exim, and that's currently but not necessarily invoked by the
php mail() function.
what I want is a function like
is_valid_mail("user12345(at)gmail(dot)com")
that will return true or false if gmail accepts the user as known (yes
the spam is always @gmail.com) WITHOUT having to write a dns mx lookup,
then connect to socket 25 and etc etc etc..
exim -bt tells me if the domain is valid, but not the user.
I am not particular how its achieved - anything can be merged into the
existing code.
anyone done this?
--
Ineptocracy
(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.
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| Re: testing email deliverability... [message #186043 is a reply to message #186040] |
Thu, 05 June 2014 04:37  |
The Natural Philosoph
Messages: 993
Registered: September 2010
Karma: 0
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Senior Member |
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On 05/06/14 04:04, Sam wrote:
> The Natural Philosopher writes:
>
>> what I want is a function like
>>
>> is_valid_mail("user12345(at)gmail(dot)com")
>>
>> that will return true or false if gmail accepts the user as known (yes
>> the spam is always @gmail.com) WITHOUT having to write a dns mx
>> lookup, then connect to socket 25 and etc etc etc..
>
> I'm afraid that you will have to wait until someone invents a telepathic
> computer, that will be able to accomplishing such an amazinf feat.
>
> Until then, unfortunately, a number of inconvenient laws of physics of
> this universe will prevent anyone from determining whether an email
> address is deliverable without looking up its MX server, and connecting
> to the MX server's port 25.
>
I meant without me having to write such code,, but it seems someone
already hass..
http://www.tienhuis.nl/files/email_verify_source.php
--
Ineptocracy
(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.
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| Re: testing email deliverability... [message #186045 is a reply to message #186043] |
Thu, 05 June 2014 04:55 |
Keith Keller
Messages: 5
Registered: June 2014
Karma: 0
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Junior Member |
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["Followup-To:" header set to comp.os.linux.misc.]
On 2014-06-05, The Natural Philosopher <tnp(at)invalid(dot)invalid> wrote:
>
> I meant without me having to write such code,, but it seems someone
> already hass..
>
> http://www.tienhuis.nl/files/email_verify_source.php
As I and others have already stated, this method is not reliable in
general, as some MXs will accept all email for its domains whether
the destination address is valid or not, in order to defeat exactly this
sort of query (done by spammers, but what defeats them defeats this
too).
All this script will do is tell you whether the MX accepted the message.
It can never tell you whether the MX delivered it to a valid mailbox,
discarded it, or generated a bounce.
--keith
--
kkeller-usenet(at)wombat(dot)san-francisco(dot)ca(dot)us
(try just my userid to email me)
AOLSFAQ=http://www.therockgarden.ca/aolsfaq.txt
see X- headers for PGP signature information
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| Re: testing email deliverability... [message #186048 is a reply to message #186047] |
Thu, 05 June 2014 12:51 |
The Natural Philosoph
Messages: 993
Registered: September 2010
Karma: 0
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Senior Member |
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On 05/06/14 11:59, AvdB wrote:
> "The Natural Philosopher" <tnp(at)invalid(dot)invalid> schreef in bericht
> news:lmoeok$5v6$1(at)news(dot)albasani(dot)net...
>> what I want is a function like
>>
>> is_valid_mail("user12345(at)gmail(dot)com")
>>
>> that will return true or false if gmail accepts the user as known (yes
>> the spam is always @gmail.com) WITHOUT having to write a dns mx
>> lookup, then connect to socket 25 and etc etc etc..
>>
>> exim -bt tells me if the domain is valid, but not the user.
>>
>> I am not particular how its achieved - anything can be merged into the
>> existing code.
>
> As an idea to work on:
>
> is_valid_mail() checks your database for known users.
There are no known users.
Or hey wouldn't be using the contact page.
> If unknown, display a 'verify first' page.
> Present a unique code which the user has to mail back to you.
> Still not 100% save, but if a user can send using a certain address,
> there's reason to believe he can receive as well. Add the user to your
> database.
Making it bloody awkward for genuine users defeats the purpose.
>
> Not enough?
> Make it a three way handshake.
> The user mails you his code, your autoresponder sends (after verifying
> the code, obviously) another unique code.
> Your form checks { is_valid_mail() or presents_valid_code() }
> You now have proof email traffic is possible in both directions.
>
>
At this point genuine enquirers have simply buggered off elsewhere.
>
--
Ineptocracy
(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.
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| Re: testing email deliverability... [message #186051 is a reply to message #186037] |
Thu, 05 June 2014 18:39 |
Adrienne Boswell
Messages: 25
Registered: October 2010
Karma: 0
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Junior Member |
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The Natural Philosopher <tnp(at)invalid(dot)invalid> wrote
> I have web contact pages which are used by anyone to send enquiries.
>
> I want to make sure that anyone using them has a valid reply address
set
> in a web form BEFORE I forward the message on to the site
administrators.
>
>
> Mailer is exim, and that's currently but not necessarily invoked by the
> php mail() function.
>
>
> what I want is a function like
>
> is_valid_mail("user12345(at)gmail(dot)com")
>
> that will return true or false if gmail accepts the user as known (yes
> the spam is always @gmail.com) WITHOUT having to write a dns mx lookup,
> then connect to socket 25 and etc etc etc..
>
> exim -bt tells me if the domain is valid, but not the user.
>
> I am not particular how its achieved - anything can be merged into the
> existing code.
>
> anyone done this?
>
>
As others have said, there really is no reliable way to do this, other
than actually sending an email and waiting for a response. Groupmail by
Infacta does have the ability to verify addresses in a list. It waits
for a response back and whatever the undeliverable response is, invalid
domain, invalid user, full mailbox, etc. This allows you to keep clean
email lists.
But, that is not going to help you in your application. I have several
email addresses, and if I want a response back to something, then I use
my primary email address. If it's something I think is going to add me
to some mailing list, then I use one of the other ones.
So, you could put something on your form like:
"Please use a valid email address. Your issue will not be addressed if
our email to you is returned."
--
Adrienne Boswell
Arbpen Web Site Design Services - http://www.cavalcade-of-coding.info/
The Good Plate - Fresh Gourmet Recipes - http://the-good-plate.com/
Please respond to the group so others can share
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| Re: testing email deliverability... [message #186056 is a reply to message #186043] |
Fri, 06 June 2014 03:36 |
Chuck Anderson
Messages: 63
Registered: September 2010
Karma: 0
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Member |
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The Natural Philosopher wrote:
> On 05/06/14 04:04, Sam wrote:
>> The Natural Philosopher writes:
>>
>>> what I want is a function like
>>>
>>> is_valid_mail("user12345(at)gmail(dot)com")
>>>
>>> that will return true or false if gmail accepts the user as known (yes
>>> the spam is always @gmail.com) WITHOUT having to write a dns mx
>>> lookup, then connect to socket 25 and etc etc etc..
>>
>> I'm afraid that you will have to wait until someone invents a telepathic
>> computer, that will be able to accomplishing such an amazinf feat.
>>
>> Until then, unfortunately, a number of inconvenient laws of physics of
>> this universe will prevent anyone from determining whether an email
>> address is deliverable without looking up its MX server, and connecting
>> to the MX server's port 25.
>>
> I meant without me having to write such code,, but it seems someone
> already hass..
>
> http://www.tienhuis.nl/files/email_verify_source.php
I feel I'm about to step into a giant pile of doo, but .... Some years
back I used a Windows program from Analogx called listmaster pro to
verify email addresses manually (it is designed to be used with large
mail lists. I never verified more than several at a time). It always
gave me correct positive and negative results. It seems to me that, in
general, an email address can be verified as a valid mailbox - or not.
There are no guarantees, of course, but this program always gave me the
correct result.
--
*****************************
Chuck Anderson • Boulder, CO
http://cycletourist.com
Turn Off, Tune Out, Drop In
*****************************
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| Re: testing email deliverability... [message #186061 is a reply to message #186056] |
Fri, 06 June 2014 13:41 |
Jerry Stuckle
Messages: 2598
Registered: September 2010
Karma: 0
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Senior Member |
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On 6/5/2014 11:36 PM, Chuck Anderson wrote:
> The Natural Philosopher wrote:
>> On 05/06/14 04:04, Sam wrote:
>>> The Natural Philosopher writes:
>>>
>>>> what I want is a function like
>>>>
>>>> is_valid_mail("user12345(at)gmail(dot)com")
>>>>
>>>> that will return true or false if gmail accepts the user as known (yes
>>>> the spam is always @gmail.com) WITHOUT having to write a dns mx
>>>> lookup, then connect to socket 25 and etc etc etc..
>>>
>>> I'm afraid that you will have to wait until someone invents a telepathic
>>> computer, that will be able to accomplishing such an amazinf feat.
>>>
>>> Until then, unfortunately, a number of inconvenient laws of physics of
>>> this universe will prevent anyone from determining whether an email
>>> address is deliverable without looking up its MX server, and connecting
>>> to the MX server's port 25.
>>>
>> I meant without me having to write such code,, but it seems someone
>> already hass..
>>
>> http://www.tienhuis.nl/files/email_verify_source.php
>
> I feel I'm about to step into a giant pile of doo, but .... Some years
> back I used a Windows program from Analogx called listmaster pro to
> verify email addresses manually (it is designed to be used with large
> mail lists. I never verified more than several at a time). It always
> gave me correct positive and negative results. It seems to me that, in
> general, an email address can be verified as a valid mailbox - or not.
> There are no guarantees, of course, but this program always gave me the
> correct result.
>
And how did it know?
For instance - I have three domains. You can send and email to any
address at any of the three. But unless it's a valid address, the email
ends up in /dev/null.
--
==================
Remove the "x" from my email address
Jerry Stuckle
jstucklex(at)attglobal(dot)net
==================
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| Re: testing email deliverability... [message #186063 is a reply to message #186062] |
Fri, 06 June 2014 15:46 |
The Natural Philosoph
Messages: 993
Registered: September 2010
Karma: 0
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Senior Member |
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On 06/06/14 15:37, Denis McMahon wrote:
> On Fri, 06 Jun 2014 09:41:05 -0400, Jerry Stuckle wrote:
>
>> On 6/5/2014 11:36 PM, Chuck Anderson wrote:
>
>>> I feel I'm about to step into a giant pile of doo, but .... Some years
>>> back I used a Windows program from Analogx called listmaster pro to
>>> verify email addresses manually
>
>> And how did it know?
>
>> For instance - I have three domains. You can send and email to any
>> address at any of the three. But unless it's a valid address, the email
>> ends up in /dev/null.
>
> Which brings us back round to:
>
> The only way to guarantee that an email address is actually going to the
> entity that entered it on your form is to send a verification code to the
> email address.
>
> And even then, I suspect that there are some smart spamming systems out
> there that have email addresses and use eg curl to process the email
> verification links (which is why I use entity and not person above).
>
I juts love all this 'guarantee' when getting spam don from 99 to 1
would be a satisfactory result.
I don't care if I get false negatives ads long as the 99 true negatives
get rejected.
--
Ineptocracy
(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.
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