On 2009-08-20, Randal L. Schwartz <merlyn@stonehenge.com> wrote:
>>>>>> "Clemens" == Clemens Schwaighofer <clemens_schwaighofer@e-gra.co.jp> writes:
>
>Clemens> I am not going to defend any regex here, but in my opinion it helps on
>Clemens> what I want to see in email addresses.
>Clemens> Yes it fails on mobile, but I have not yet seen one.
>
> And that's the problem. You get near-sighted if you put up a strong
> validation for only things that *you* have seen. Because, guess what,
> nobody outside your narrow view can sign up or be a customer.
>
> Bad for business.
>
>Clemens> Probably the best
>Clemens> thing is to test nothing at all. Just accept it ...
>
> Exactly! If you don't want to use the 950-character regex, DON'T DO
> ANYTHING AT ALL. Far simpler.
Or do an MX lookup on the domain part (or a partial attempt to route
mail*) before sending it to the database.
*contact the domains MX and in SMTP go as far as "RCPT TO: ... " and
then send "QUIT" after it is accepted or refused.