I have a request from my client asking for an alert to be generated whenever a user sends an email to a freemail service such as gmail. Client has a huge list of exception and whenever I try to implement this with a Compliance DLP rule's exception related to the recipient's domain, I get an error stating that "The generated rule blob is too long. The maximum length is 81920 and the length of the rule blob is 256040.". I tried to split the exclusion list between several rules in the same DLP policy but I get a lot of false positive. Any idea if this limited size can be overriden ?
I guess that it would be better to implement this in Exchange but does Exchange Rules have the same kind of size limit ?