Why Cloud Servers are Bad for Sending Email?
The IP address spaces used by the major public cloud vendors (i.e. Amazon, Rackspace, etc.) for their cloud servers are well known and are generally black- or gray-listed by anti-spam systems. Additionally, many of the IP addresses in use by these systems are additionally “polluted” from previous abusive use by spammers. When you set up a new cloud server, you could be easily assigned a “tarnished IP.” Even if you do not inherit an exceptionally bad IP reputation from the previous user(s) of your new IP, your server will still be in the uncertain neighborhood of “public cloud IP addresses.” This is the “wrong side of the tracks” and thus considered a possible spam source.
We have investigated several services that claim to offer “Cloud-Based Outbound Email” and have found that many use cloud servers for things like scanning email messages for spam and viruses, but use non-public cloud servers for the actual sending of email. This is obviously not true for all companies, but it points to the fact that if everyone might be affected, the solution is to NOT send email directly from your public cloud. There are, however, straight-forward solutions to getting email originating from such servers delivered.
Read the rest of this post »