Wanted to get the communities input on how to deal with e-mail providers like Office365.
I receive e-mail from a lot of shops that use Office365 as their e-mail provider and what I'm finding is a lot of Office365s servers have very poor reputations for SPAM. Right now they have over 100 IP address that have a SBRS score of -3.0 or worse. A poor Office365 tenant has no control over what server their e-mail comes from (or do they know what IP, other than .outlook.com) within the Office365 cloud and intermittently it will be sent from an IP that has a poor reputation. Well, then my system, protected by IronPort filtering sees that poor SBRS reputation and says no way, so then the sender gets all upset and contacts the recipient (my customer) and the recipient doesn't know what to tell them, so they say, send it to GMAIL account, and more times than not it works. Making it seem that the problem is on my end when in all reality it is on the senders end because they are hosted on an environment that has a poor reputation SMTP server.
To resolve the problem the best answer that I can come up with is to add .outlook.com to a policy that ignores SBRS scores, allowing ALL of them to connect to my appliances and send all kinds of garbage that most (if there is a definition for it) get filtered out before getting to my users mailboxes but at the expense of my environments resources. But ultimately some gets through because its new and we report it to Cisco but this doesn't improve the volume of garbage that Office365 can send me, only the amount that I have to filter out from them. Can't throttle the volume of e-mail down to a helpful level accepted from Office365 as we already have a high volume of legitimate e-mail coming from it.
Anyway, wanted to get the communities input on this, is there a better answer, and how this is going to work moving forward with more and more organizations moving to cloud providers where they have a large number of organizations hosted on one environment.
Jason
