E-mail validation with preg_match

[patricktr]

Hi,

I've picked up a simple e-mail vaildation string from one of the forums which seems to work (most times)...

I've just hit a problem where it is rejecting an e-mail address and I can't see why.

The vailidation statment is....

if (preg_match("/^([a-z0-9]([a-z0-9_-]*\.?[a-z0-9])*)(\+[a-z0-9]+)?@([a-z0-9]([a-z0-9-]*[a-z0-9])*\.)*([a-z0-9]([a-z0-9-]*[a-z0-9]+)*)\.[a-z]{2,6}$/", $address))
{ return true; }
else
{ return false; }

.. but it doesn't like the bit after the '@' sign to be more than 16 characters long in total which I don't get.

So
a.b@1234567890123.com is invalid whilst
a.b@123456789012.com and a.b@1234567890123.uk are both valid?

Can anyone help please?
Regards.
Patrick.

[Newsgroup_User]

.oO(patricktr)

> I've picked up a simple e-mail vaildation string from one of the forums which
>seems to work (most times)...

Proper regex-based email validation is almost impossible. For an example
see this little pattern, which is still incomplete:

http://www.ex-parrot.com/~pdw/Mail-RFC822-Address.html

And even if the address appears to be syntactially correct doesn't mean
that it exists. The only way to be sure is to actually send a message
and have the user respond.

> I've just hit a problem where it is rejecting an e-mail address and I can't
>see why.
>
> The vailidation statment is....
>
> if
>(preg_match("/^([a-z0-9]([a-z0-9_-]*\.?[a-z0-9])*)(\+[a-z0-9]+)?@([a-z0-9]([a-z0
>-9-]*[a-z0-9])*\.)*([a-z0-9]([a-z0-9-]*[a-z0-9]+)*)\.[a-z]{2,6}$/", $address))
> { return true; }
> else
> { return false; }

Such patterns will always reject a lot of valid addresses and allow many
invalid ones (hint: there are a _lot_ more chars allowed than just ASCII
letters and digits!). And this pattern doesn't even allow uppercase ...

If it has to be a regex check, I would simply check for a single '@' and
some string before and after it.

Micha

[patricktr]

Thanks Micha. I appreciate what you are saying and I knew that the statement was far from all-encompassing but I can't see why it is limiting the bit beyond the '@' sign to 16 chars? Does any know or has anyone got a better, simple e-mail address validator.

P.