[csnover]

Whatever the problem is, all I know is that last year Linode said they tried and failed to get Microsoft to actually fix the problem[0], apparently despite assurances and multiple requests for a root cause analysis. Everyone else seems to have figured out how to not be overrun by spam and also not block entire netranges, so I’d say it is well past time for Microsoft to figure out how to do that too.

Thanks and good luck!

[0] https://www.linode.com/community/questions/22287/550-57511-a...