* On Fri, 2008-04-04 at 08:24 +0100, Mark Rogers wrote:
Now that we have cleared the problem their IP address has been removed from the blacklists, although that's not a problem now as we configured their mail server (Exchange - horrible thing) to send via the ISP's smart host.
This got me thinking: Are there any voluntary blocklists where you can subscribe IPs that should never send any email, and so any email from that IP should be assumed to be spam?
I wouldn't do that
Some spam filters look through the session transcript and block a message if *any* IP address or host mentioned in it is blacklisted not just the last relay. So for example using this message as an example when it says
Received: from 87-127-158-124.no-dns-yet.enta.net ([87.127.158.124] helo=msl-office.co.uk
Even though you are using the.earth.li as a relay it will get blocked if 87.127.158.124 is blacklisted.
The best way is to lock down their gateway so only the Exchange box can send SMTP or if you want to go one step further lock it down so that only the exchange box can send smtp to only your relay server.