| Author | Topic: checking for mail server using xb2net | |
|---|---|---|
 | Nestor G. Torres | checking for mail server using xb2net on Fri, 06 May 2011 17:52:17 +0200 |
| Rudolf Reinthaler | Re: checking for mail server using xb2net on Sat, 07 May 2011 11:39:16 +0200 |
| Nestor G. Torres | Re: checking for mail server using xb2net on Sat, 07 May 2011 14:34:47 +0200 |
| Andreas Gehrs-Pahl | Re: checking for mail server using xb2net on Sat, 07 May 2011 17:32:03 -0400 Nestor,
>After a little bit of experimentation and reading the xb2help I came up
>with a possible solution which is very quick.
>The solution is to strip away the "username@" from the email address and
>then check the rest for a valid domain/host name.
Because "GetHostByName()" is a Class Method, you don't need to instantiate
an "oSocket" object with "oSocket := XbSocket():New()". But if you do, you
should destroy it, after you are done with it. So the following code would
be shorter and better:
aResult := XbSocket():GetHostByName("softwareclinic.co.za")
But if you don't have internet access or the DNS server is out, you might
get a false negative, even with this simple test.
>If the domain/host name is valid on the internet then the chances that the
>email address provided is good is probably 90% ...
>that would not be a bad hit rate. Please let me know if I am being simple
>mined or maybe I am not getting it.
It completely depends on the source for your email address. Even if the
domain name exists, there is no way to tell if the actual email address
is valid, active, or who it belongs to. If you get the email address from
a customer, and you want to simply check if it isn't obviously wrong, you
could check the following:
1) Does the domain name exist? (see above)
2) Does the email address only contains valid characters?
But to be sure that the email is really valid -- and even belongs to that
customer -- you would also need the following tests:
3) Can you send an email to that address or is it bouncing?
4) Does the recipient of the email send you a validation response?
Using only the first two tests will probably give you a 10% success rate
at best, if you allow anonymous email address submissions, for example on
a web site. But if the customer stands right in front of you when telling
you the email address -- or has something to gain from given you a valid
email address -- the success rate will go up, and might reach something
like 75% to 80%.
On the other hand, 87% of all statistics are made up on the spot, so I
really don't know how accurate any of this would be. Andreas Gehrs-Pahl
Absolute Software, LLC
phone: (989) 723-9927
email: Andreas.GP@Charter.net
Andreas.Gehrs-Pahl@EJusticeSolutions.com
Andreas@DDPSoftware.com
web: http://www.Aerospace-History.net |
| Nestor G. Torres | Re: checking for mail server using xb2net on Sun, 08 May 2011 10:08:43 +0200 Hi Andreas,
Thank you so much for your constructive comments.
1) Valid characters and proper format of the email address is what I look
for...so your point on that issue is covered. And thank you for clarifying
that with this group.
2) Your additional simplification of GetHostByName call is an excellent
observation. less cpu and code waist.
3) I agree that that the domain name can only be checked using a adsl or 3g
connection to the internet.
And that yes the DNS server could be down giving us a bad connection
reading; but that would not be
the normal case.
4) Yes our customers are in front of the operators when these emails are
captured; which is as you stated the best case for
valid email capturing.
5) The process of validating email addresses to the hilt is to time
consuming and would be counter productive.
So your guestament of 75- 80% is still a very good hit rate for us.
Again thankyou for your thoughts which have helped me crystalize mine a bit
more.
Kind Regards,
Nestor
"Andreas Gehrs-Pahl" wrote in message
news:13frt742wytz2.pas8tuv1yu8k.dlg@40tude.net...
> Nestor,
>
>>After a little bit of experimentation and reading the xb2help I came up
>>with a possible solution which is very quick.
>>The solution is to strip away the "username@" from the email address and
>>then check the rest for a valid domain/host name.
>
> Because "GetHostByName()" is a Class Method, you don't need to instantiate
> an "oSocket" object with "oSocket := XbSocket():New()". But if you do, you
> should destroy it, after you are done with it. So the following code would
> be shorter and better:
>
> aResult := XbSocket():GetHostByName("softwareclinic.co.za")
>
> But if you don't have internet access or the DNS server is out, you might
> get a false negative, even with this simple test.
>
>>If the domain/host name is valid on the internet then the chances that the
>>email address provided is good is probably 90% ...
>>that would not be a bad hit rate. Please let me know if I am being simple
>>mined or maybe I am not getting it.
>
> It completely depends on the source for your email address. Even if the
> domain name exists, there is no way to tell if the actual email address
> is valid, active, or who it belongs to. If you get the email address from
> a customer, and you want to simply check if it isn't obviously wrong, you
> could check the following:
>
> 1) Does the domain name exist? (see above)
> 2) Does the email address only contains valid characters?
>
> But to be sure that the email is really valid -- and even belongs to that
> customer -- you would also need the following tests:
>
> 3) Can you send an email to that address or is it bouncing?
> 4) Does the recipient of the email send you a validation response?
>
> Using only the first two tests will probably give you a 10% success rate
> at best, if you allow anonymous email address submissions, for example on
> a web site. But if the customer stands right in front of you when telling
> you the email address -- or has something to gain from given you a valid
> email address -- the success rate will go up, and might reach something
> like 75% to 80%.
>
> On the other hand, 87% of all statistics are made up on the spot, so I
> really don't know how accurate any of this would be. |
| Rudolf Reinthaler | Re: checking for mail server using xb2net on Sun, 08 May 2011 10:20:51 +0200 |
| Nestor G. Torres | Re: checking for mail server using xb2net on Sun, 08 May 2011 11:16:52 +0200 |
Andreas