The requirement was to harden Active Directory as close to the Secure Domains recommendations in the SSLF documentation. Part of this requirement was to restrict the Manage Security and Auditing user right, which knocked out Exchange Enterprise Servers from the list. One Exchange server was rebooted.
All messages on the server started queuing up - both SMTP and MSExchangeMTA. The various messages on local and remote servers included "unable to bind to DNS", "client attempted to use LOCAL AUTHORITY/ANONYMOUS LOGON".
SMTP queues were cleared by setting up one of the other Exchange servers as a smart host. This short-circuits the internal Exchange<>Exchange comms (and authentication) and uses pure SMTP.
Relevant user rights are back in place and DC replication is working.
Attempts to trick MTA service into using service, user or computer accounts failed.
/domainprep and /forestprep have been re-run.
PolicyTest has been run and confirms SeSecurityPrivilege is present on all DCs.
Please focus on specifics of the problem, rather than general offers of AD/Exchange health. I am looking for an alternative method of confirming / testing / reapplying the standard security necessary at domain level for correct functioning of Exchange.
For example, would reinstalling troubled Exchange Server perform anything that /domainprep and /forestprep don't; or, are there Registry settings which could silently override GPO settings at DC Def Policy etc.
Thank you in advance.