Re: [exim] Testing sending hosts open ports

Gareth Hastings wrote:
>> 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)
>
I wasn't going to use this test by itself. Just wondering if it could be
done. I was thinking of some way to examine the sender to see if it
looked like it was a home computer running Windows XP as opposed to a
server. And this was just one aspect of the test. I might look at ports
135 and 139 and 455(?) etc. The idea being is this the computer has all
the windows ports open and is not a Windows 200[03] server, and maybe on
a dynamic IP then I might reject it. So the idea wasn't to just check if
port 25 is closed, but check of 25 is closed and other ports are open.