| YMMV The spamhaus list changes daily. You should also look at the spam volume by domain at Senderbase, where Google, Sprint, and Verizon have been in the top 10 for months. What is interesting in contrasting Spamhaus and Senderbase is that the Spamhaus one looks at a small set of bad IPs, which obviously is easier to clean up. Senderbase looks at all of the IPs in a given network, including the IPs of subscribers rather than just official mail and other servers. As a result, the Senderbase numbers for ISPs often show how bad their outbound spam is, usually due to botnets and phishing sites.
For portals like Google and Yahoo and Hotmail, the issue is due to the cracking of their captcha systems that allow web sites and documents to be created in bulk for malicious use.
This seems to have finally made the light of day - but this is the sort of problem that can't be cleaned up in a day. |
