After offering unlimited redirects/mail fowarding in our shared hosting plans for many years, we are only offering unlimited redirects to our clients who have E Street’s Spam and Virus filtering service.
Although not ideal, we had a very good reason for putting this in place. We found that our e-mail servers were constantly being blocked by providers like AOL, MSN, Google, Yahoo and other Internet service providers. This was keeping our clients and our own e-mails from reaching the intended recipients. It was a daily chore for us to try to keep our e-mail servers from being blocked.
Our first assumption was that our business clients were sending messages to their mailing lists and the users were inadvertently marking them as spam. After x number of reports of spam, our e-mail server would get blocked. After installing hardware to monitor outgoing messages for spam, we were able to determine that redirects for addresses without any spam filtering were the cause of the trouble. The amount of spam going through the redirects wasn’t small either. It was in the order of 10s of thousands per day. It was no wonder we were being blocked, we looked like a spam relay!
So, we decided that we could only allow redirects on addresses that have our spam and virus filtering. This knocks out 95 percent of the spam being redirected.
Since we instituted this policy in early 2008, we went from multiple e-mail servers being blocked per day, to ZERO blocks in the first 3 months! Yes, you read that right, we completely eliminated the problem by requiring redirected addresses to first be scanned for spam.