On Thu, 2004-01-22 at 09:31, Richard Miller wrote:
> UUG:
>
> A line in my PHP script tests for bad email addresses with the
> following regular expression:
> ...
> if (!ereg("[EMAIL PROTECTED],5}$", $email))
Just want to mention that one of my pet peeves is web sites that think
that email addresses with a "+" in the name aren't valid. They are
valid and rfc compliant. Technically you might want to allow them. For
example, [EMAIL PROTECTED] is a valid e-mail address. Just for
those that don't know how the plus sign is treated, according to the
SMTP RFC's, mail clients should accept e-mail addresses with a plus sign
in it, but for the purposes of delivery, everything after the plus sign
is ignored. This allows for some cool filtering and spam prevention.
For example, all my e-mail communication with comcast is done with
torriem+comcast. If I start getting spam that is being sent to
torriem+comcast, then I know who sold my address and then I can block
all mail with the "+comast" suffix.
> ...
>
> However, this expression evaluates email addresses like
> [EMAIL PROTECTED]" and "[EMAIL PROTECTED]" as incorrect.
> It's the subdomain or two dots after the @ sign that causes the
> problem. How can I change my expression above to allow email addresses
> with subdomains?
Perhaps tonight at the UUG meeting we'll gleen the necessary information
on regular expressions to make this work. At the moment, without
spending a lot of time trying things I don't have any helpful advice,
unfortunately.
>
> Also, if I am going to worry about (and allow) email addresses that
> have 2 dots after the @ sign, should I worry about there being email
> addresses with 3 or more dots? What expression would handle an
> infinite number of dots after the @ sign?
In theory, an address could have any number of "." separators after the
@ sign. In practice I don't know of any really deep domains like that,
but there is certainly nothing in the RFCs that would preclude it.
Michael
>
> Thanks!
>
> Richard
>
> (Am I asking this just 10 hours premature?)
>
>
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--
Michael L Torrie <[EMAIL PROTECTED]>
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