I added Deutsche Telekom and Kabel Deutschland to my white list and I am waiting to see if I get spam from these ip blocks. I had them black listed for a while, but I received a couple of reports from residential customers not making it through. If I start getting lots of spam I will turn them off again.
I am white listing Amazon AWS because the blacklist was stopping some important web services that I use. I am going to turn the block back on and white list individual IP addresses again. AWS lets spammers mount an instance and start spamming for free. They shut them down right away, but in the mean time I get a few hundred spammers or hack attacks. Until they start requiring a credit card I can’t let AWS into my site.
The most troubling white list was Tiscali Italia. I put them on the white list and got a huge spam hit. I think that Tiscali Italia does not keep ahead of the game as far as zombie computers on their network.
I think that I am going to start tracking individual IPs on white listed networks. If I get a confirmed spam I will block just the IP and keep on white listing the block. This will mean managing a growing list of single IP addresses, and perhaps timing them out after a few weeks. Blocking a range is so much easier. This requires a bit of coding and I probably won’t get to it right away, but it is something that needs to be done.
As far as Tiscali Italia goes. I am watching it and will probably black list it again. My Italian customers will have to use other sites to get what they need.
I am also considering making a static subdomain for each of my domains so that blocked users can view the data, but not have access to the php files.