NetComrade wrote:
> We have whitelisted our domain, but now we have spam coming from users that
> claim they're in our domain.
>
> What's the best way to fight it?
The best way is to reject it at smtp time. It must be done at smtp
time because rejecting at any other time would cause you to be a
source of backscatter spam and you would not want that. If you can't
reject at smtp time then the best that you can do is to discard the
spam later which means that you can't whitelist your own domain and
will have to scan for it the same as any other suspect mail.
The best reference of which I am aware for rejecting at smtp time is
the one for Postfix. If you are using Postfix for your MTA then this
will slip right in. If you are using something else then I don't
know. This is what I am using and it works very well for me. YMMV.
http://www.postfix.org/BACKSCATTER_README.htmlBob
