Comment 46 for bug 224971

Good you have corrected the issue. Methods like IP blocking or contacting ISP's are not likely to help. IP's change extremely rapidly using many different techniques, and the Host vendors are also usually already seven levels deep and unreachable, through other quasi-legal business practices. Email banning is also fruitless. Increased restrictions on levels of access, and human review and intervention (like you have done) seem to be the most efficient methods. If possible, have a human review each new registration and web search the email name and IP address. Most often the email name/address, in some form, has been already associated with spamming and the IP's will show on websites like stopforumspam.com. It is how I located the problem here. Jintan