Email address spoofing

[Alex Neuman van der Hans]

Exactly. If they're using someone else's mailservers there is nothing  
to do.

Stop them from using another server if you really want to solve the  
problem.

If your users say "but I can't connect to your server" help them out  
by using port 465 and port 587 (with and without SSL). Port 25 is not  
a prerequisite; in fact, it should be discouraged unless you're a  
server.

On Oct 2, 2008, at 11:59 AM, Maxime Gaudreault wrote:

> 2. My mail server already uses authentication. But my customers uses
> their ISP's mail server... not mine.
>
> 3. I'm not sure I understand but if they don't use my outgoing  
> server, I
> can't signs the emails..