> Just wondering how to do this. I'd like to test to see if the sending
> host at port 25 open. Would this be a good way to detect spammers? Would > a host sending email to my host not have port 25 open to receive email?
I think this would be a bad test also. Often people who use smart hosts
or have outsourced spam/AV management tend to restrict access to their
mail servers to only the relevant hosts (i.e. upstream relays etc)
