Don:

> I have been working on a program to validate email
> addresses (syntax only) =
> to filter out obviously bad addresses from internal
> files/databases prior =
> to loading into a listserv list.  My questions are "what is
> a valid email =
> address?", and "where do I go to find the authorative
> definition?"

I don't know what platform you're developing this for, but a couple of
years ago, Tom Christensen sent me a perl script that we've been using
for some time to do as much error checking as possible on form-input
e-mail address submisstions. It's not a big script but I suspect it
will not run on all platforms (we run it on a UNIX platform). If you
know perl, I suppose you could convert the logic to another language.
The program checks for all the potential syntax errors and also has
some editorial filters (many of which I deleted) that screen out
usernames like "webmaster" or "username" or "root" or that have
repetive characters in them (i.e. [log in to unmask]). It also
validates the deliverability of the domain by checking if there is an
MX record for the domain.

Beyond that, final validation of e-mail is confirmed when an actual
attempt to deliver is made.

If you like, I can send you that script privately.

Mark Hunnibell