This is an Exchange email sending problem that has been plaguing me for a very long time, for many clients and I am now left with no option but to resolve it once and for all.
We have about 80 Small Business Servers that we manage and maintain for our clients. The MS Server operating systems in question are SBS 2003, 2008 and 2011.
Our client base use a wide variety of Broadband providers in the UK and their SMTP relay services / policies are very varied. About 30 of our clients use broadband providers that do not provide a free SMTP service as part of their broadband package and as a result, we are forced to either use a 3rd party provider or set the Server to route through DNS (only 3 or 4). Clients routing through DNS get many bounce backs from ISPs stating they have been denied due to SPAM filter rules.
As I am sure you are all aware, most ISPs block emails to the clients that are sent from DNS because they are classed as SPAM. The total bill for the 3rd party providers is beginning to increase and I need a free or cost affective solution.
Do I need to register the clients domain names with the ISPs or setup special A records to verify where the emails come from ?
Any help or guidance is greatly appreciated