What is agent blacklisting?
When computer X merges into computer Y then X gets into the AgentBlacklist table as well X disappears as a resource at NS. However agent still has GUID X and thinks it is allright. AgentBlacklist table tells NS which computers are not allowed to receive policies and whose NSEs (X, for example) should not be processed.
Note: In case merge was automatic (X was merged into Y due to equal resource keys) Z = Y, thus we will have 2 machines sharing the same GUID. The ONLY workaround in such case in SMP 7.6 is to make sure all the resource keys are unique for the problematic pair of computers. It is not always possible.
There are 2 filters that are supposed to be managed by users manually. The purpose of these filters is to tell NS what computers should stop receiving policies - all the policies or user-based policies. The use-cases for maintenance of these filters are undefined. However here is what they technically do:
Both filters are regular filters, so they may contain either explicit resources or be query-based.
TECH & HOWTO articles
The article relates to blacklisting caused by computer merge. In this case the blacklisted computer should get the special error code NFYSVR_E_NOT_FOUND indicating that resource does not exist on NS and client agent should CHANGE its GUID. This article was probably written in times when agent GUID change did not work properly at the agent side. It should be no longer applicable to 7.5 and higher agents
Pretty well described how automatic blacklisting works
This references some bugs that have been fixed in 7.5 and not applicable for 7.6
It describes merging in hierarchy. It is related to the automatic blacklisting.