Verify an e-mail-adress - syntax and dns

[Frithiof Andreas Jensen]

"Ingo Linkweiler" <ingo.bear_NOSPAM at freenet.de> wrote in message
news:ef5nop$aoh$1 at news01.versatel.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 at hdhjdfhjh.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!