[Greylist-users] Re: Empty MAIL FROM:

[Evan Harris]

The RFC's are very non-specific about what the user part of the email
address may be, since different systems have different restrictions on the
formatting for user account names.  Theoretically, * may be a valid address
on some type of system.

However, in the real world, you can infer that such mail is spam, though it
becomes difficult to describe a rule for detection that is not also prone to
the possibility of false rejections.

I would think a rule that any userpart that doesn't contain any alphanumeric
characters is a faked address.  However, any such rule will only be useful
as long as spammers don't bother to forge a real looking return mail
address, which it is very trivial to do.

Evan


On Sat, 23 Aug 2003, richard at stardate.ca wrote:

> Thanks for the advice and clarification.
>
> I had stopped bouncing the empty MAIL FROM: before I posted to the list.
>
> What about a MAIL FROM: that contains <*@somedomain.com>, or other forms
> of invalid email addresses, good or bad to bounce?