There are two issues of importance to Earthlink subscribers:
Our listing of Earthlink IPs is a direct result of complaints about spam sent by the Church of Scientology through Earthlink. Scientology sent spam to people who specifically requested not to receive their email. Moreover, they have failed to remove rejected addresses from their lists. Poor list management (in this case an apparent lack of any list management) puts a strain on corporate servers receiving email intended for former employees, some of which has to be read prior to deletion.
We have communicated several times with Earthlink and have sent them a copy of every “removal” request yet they fail to take action or even respond. Meanwhile, the list of IPs expands.
The second problem is that Earthlink has created a challenge/response (C/R) system that subscribers can use to control spam. C/R creates far more spam than it filters. The reason for this is that the majority of spam depicts an innocent user as the sender. Thus, if a spammer does a run using my return address in the email, I may receive thousands of spam challenge messages. Most people consider those messages to be spam.
Administrators: These challenges can be detected with a sender check on email@example.com or header checks on “Reply-to: firstname.lastname@example.org”