Does Microsoft Operations Manager (MOM) require Active Directory (AD)?

A. Yes. All versions of MOM require AD, even MOM 2005 Workgroup Edition. This doesn't mean that every server that MOM monitors has to be in the same domain as MOM. Only the MOM management server requires membership to an AD domain, and if managed servers are in the same AD forest, mutual authentication can be used. However, you can disable this extra security to allow management of computers outside the local forest.