Verify an e-mail-adress - syntax and dns

[Ingo Linkweiler]

Has anyone a function/script to verify an e-mail-address?

It should:
a) check the syntax
b) verify an existing mailserver or DNS/MX records

ingo

[Bjoern Schliessmann]

Re: Verify an e-mail-adress - syntax and dns

Ingo Linkweiler wrote:

b) verify an existing mailserver or DNS/MX records

"Or"? That's two different things.

If you don't know already: Even if you test all this, it is still
possible that

- the target mail account doesn't exist
- the sender's IP is filtered by the server so he'll reject
- the localpart has syntax errors (allowed chars in the localpart
are up to the server)

Regards,


Björn

--
BOFH excuse #280:

Traceroute says that there is a routing problem in the backbone.
It's not our problem.

[Ingo Linkweiler]

Re: Verify an e-mail-adress - syntax and dns

Bjoern Schliessmann schrieb:

Ingo Linkweiler wrote:
>

>b) verify an existing mailserver or DNS/MX records

>
"Or"? That's two different things.
>
If you don't know already: Even if you test all this, it is still
possible that
>
- the target mail account doesn't exist
- the sender's IP is filtered by the server so he'll reject

Yes, I know this.
But its still better than not checking it.
The script will be used as part auf a user registration page to avoid
dummy-inputs like "jsfhsadgfa@hdh jdfhjh.net"

[Marc 'BlackJack' Rintsch]

Re: Verify an e-mail-adress - syntax and dns

In <ef5nop$aoh$1@n ews01.versatel. de>, Ingo Linkweiler wrote:

The script will be used as part auf a user registration page to avoid
dummy-inputs like "jsfhsadgfa@hdh jdfhjh.net"

The usual way to cope with this is sending out confirmation mails. No
need to check if the address is syntactically correct beforehand.

Ciao,
Marc 'BlackJack' Rintsch

[Ingo Linkweiler]

Re: Verify an e-mail-adress - syntax and dns

The usual way to cope with this is sending out confirmation mails. No

need to check if the address is syntactically correct beforehand.

yes, I do this allready. But it would be nice to do some checks before
to avoid wrong user inputs.

[Bjoern Schliessmann]

Re: Verify an e-mail-adress - syntax and dns

Ingo Linkweiler wrote:

yes, I do this allready. But it would be nice to do some checks
before to avoid wrong user inputs.

What do you do if the user inputs a "wrong" address? If you reject
with an error message, the medium intelligent user will enter
something like

sdjfgsdjhg@gmx. net

as next try, circumventing your test.

Regards,


Björn

--
BOFH excuse #178:

short leg on process table

[Ben Finney]

Re: Verify an e-mail-adress - syntax and dns

Bjoern Schliessmann <usenet-mail-0306.20.chr0n0s s@spamgourmet.c omwrites:

Ingo Linkweiler wrote:
>

yes, I do this allready. But it would be nice to do some checks
before to avoid wrong user inputs.

>
What do you do if the user inputs a "wrong" address? If you reject
with an error message, the medium intelligent user will enter
something like
>
sdjfgsdjhg@gmx. net
>
as next try, circumventing your test.

I believe Ingo is checking for the case where the user intended to
enter a valid email address, and made a typing error resulting in a
trivially invalid one.

--
\ "'Did you sleep well?' 'No, I made a couple of mistakes.'" -- |
`\ Steven Wright |
_o__) |
Ben Finney

[Bjoern Schliessmann]

Re: Verify an e-mail-adress - syntax and dns

Ben Finney wrote:

I believe Ingo is checking for the case where the user intended to
enter a valid email address, and made a typing error resulting in
a trivially invalid one.

Ah. Good intention, but the same applies: Typos in the localpart are
not detectable. Typos in the domain part could mostly be easily
corrected by hand, too.

Regards,


Björn

--
BOFH excuse #297:

Too many interrupts

[Frithiof Andreas Jensen]

Re: Verify an e-mail-adress - syntax and dns


"Ingo Linkweiler" <ingo.bear_NOSP AM@freenet.dewr ote in message
news:ef5nop$aoh $1@news01.versa tel.de...

Bjoern Schliessmann schrieb:

Ingo Linkweiler wrote:

b) verify an existing mailserver or DNS/MX records

"Or"? That's two different things.

If you don't know already: Even if you test all this, it is still
possible that

- the target mail account doesn't exist
- the sender's IP is filtered by the server so he'll reject

>
Yes, I know this.
But its still better than not checking it.
The script will be used as part auf a user registration page to avoid
dummy-inputs like "jsfhsadgfa@hdh jdfhjh.net"

Why bother, you will loose anyway:

For those kind of sites demanding registration for trivial usage (i.e. most
sites do) I use my own domain controlled by myself - the adress is valid for the
confirmation mail then, after I got what I came for (or after I found out that
this site was a waste of time, which happens entirely too often), the adress is
not valid anymore.

Cuts down the spamvertising a lot!

[Steven D'Aprano]

Re: Verify an e-mail-adress - syntax and dns

On Sun, 24 Sep 2006 13:23:03 +0200, Ingo Linkweiler wrote:

>The usual way to cope with this is sending out confirmation mails. No
>need to check if the address is syntactically correct beforehand.

>
yes, I do this allready. But it would be nice to do some checks before
to avoid wrong user inputs.

Because you like reinventing the wheel and doing the same work twice?

By memory, in an thread about the same topic just a few days ago, Fredrik
Lundh posted a link to Perl's FAQs that suggests a method for "validating "
email addresses: treat it like a password and ask the user to type it
twice. That will protect against simple typos and input errors.

For everything else, send to it and see what happens.


--
Steven D'Aprano

[Christophe]

Re: Verify an e-mail-adress - syntax and dns

Steven D'Aprano a écrit :

By memory, in an thread about the same topic just a few days ago, Fredrik
Lundh posted a link to Perl's FAQs that suggests a method for "validating "
email addresses: treat it like a password and ask the user to type it
twice. That will protect against simple typos and input errors.

I hate that thing. When I see that, I type my email once and copy/paste
into the second edit box. This is useless AND annoying at the same time.

[Steve Holden]

Re: Verify an e-mail-adress - syntax and dns

Christophe wrote:

Steven D'Aprano a écrit :
>

>>By memory, in an thread about the same topic just a few days ago, Fredrik
>>Lundh posted a link to Perl's FAQs that suggests a method for "validating "
>>email addresses: treat it like a password and ask the user to type it
>>twice. That will protect against simple typos and input errors.

>
>
I hate that thing. When I see that, I type my email once and copy/paste
into the second edit box. This is useless AND annoying at the same time.

Probably safe to say it's a little less useful when the text field
contents are visible, but the classic validator for hidden fields.

It might surprise you to realise that not everyone in the world is a
touch typist, and for them (since they are often looking at the keyboard
rather than the screen) it's not an unreasonable validator.

regards
Steve
--
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Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://holdenweb.blogspot.com
Recent Ramblings http://del.icio.us/steve.holden

[Georg Brandl]

Re: Verify an e-mail-adress - syntax and dns

Christophe wrote:

Steven D'Aprano a écrit :

>By memory, in an thread about the same topic just a few days ago, Fredrik
>Lundh posted a link to Perl's FAQs that suggests a method for "validating "
>email addresses: treat it like a password and ask the user to type it
>twice. That will protect against simple typos and input errors.

>
I hate that thing. When I see that, I type my email once and copy/paste
into the second edit box. This is useless AND annoying at the same time.

It may be for you, but there certainly are users that misspel their
e-mail address more frequently, just like passwords. And therefore it's a
nice touch to spare both the original submitter and the owner of the
misspelled address more work.

Georg

[Christophe]

Re: Verify an e-mail-adress - syntax and dns

Georg Brandl a écrit :

Christophe wrote:

>Steven D'Aprano a écrit :

>>By memory, in an thread about the same topic just a few days ago,
>>Fredrik
>>Lundh posted a link to Perl's FAQs that suggests a method for
>>"validating "
>>email addresses: treat it like a password and ask the user to type it
>>twice. That will protect against simple typos and input errors.

>>
>I hate that thing. When I see that, I type my email once and
>copy/paste into the second edit box. This is useless AND annoying at
>the same time.

>
It may be for you, but there certainly are users that misspel their
e-mail address more frequently, just like passwords. And therefore it's a
nice touch to spare both the original submitter and the owner of the
misspelled address more work.

Which proportion of the people that sometimes misspell their e-mail also
use cut&paste when faced with "please type your e-mail twice" web pages?

[Christophe]

Re: Verify an e-mail-adress - syntax and dns

Steve Holden a écrit :

Christophe wrote:

>Steven D'Aprano a écrit :
>>

>>By memory, in an thread about the same topic just a few days ago,
>>Fredrik
>>Lundh posted a link to Perl's FAQs that suggests a method for
>>"validating "
>>email addresses: treat it like a password and ask the user to type it
>>twice. That will protect against simple typos and input errors.

>>
>>
>I hate that thing. When I see that, I type my email once and
>copy/paste into the second edit box. This is useless AND annoying at
>the same time.

>
Probably safe to say it's a little less useful when the text field
contents are visible, but the classic validator for hidden fields.
>
It might surprise you to realise that not everyone in the world is a
touch typist, and for them (since they are often looking at the keyboard
rather than the screen) it's not an unreasonable validator.

Well, if they have a hard time using a keyboard, I've no doubts they
will love using cut&paste to cut nearly in half the time needed to fill
out your form :)