Comment 55 for bug 44062

(In reply to comment #53)
> I know nothing about programming, but why don't you just make it block anything
> starting with a period. No domain names have periods at the end of it.
>

That's not true. A FQDN (fully qualified domain name) has a period at the right
end. But 99.99% of all DNS names omit it, and many applications (mistakingly)
don't even accept this format.

And to counter your agument about blocking anything starting with a period, I
quote from RFC2965 :
   Domain=value
      OPTIONAL. The value of the Domain attribute specifies the domain
      for which the cookie is valid. If an explicitly specified value
      does not start with a dot, the user agent supplies a leading dot.