Microsoft/Hotmail forgot to set reverse DNS pointers?

Today I received some notices about Hotmail users who couldn't send e-mail messages to various receipients due to spamfilters blocking them at the receiving mailservers. Seems like Microsoft/Hotmail staff forgot to set some reverse DNS pointer records: Diagnostic-Code: smtp;450 4.7.1 Client host rejected: cannot find your reverse hostname, [157.55.1.150] (Verified this using various public DNS servers, to exclude potential local issues) Anyone here who has proper contacts to give them the clue-bat? -- Michiel Klaver IT Professional