fsmo- FSMO stands for flexible single master operation by the help of FSMO role we can identify which one dc ,adc,cdc having some role domainnaming master role,schema master role you know in schema master role first we have to register it regsrv32 shcmmgmt.dll this is file we have to register it and domain naming master role ,rid,pdc,infrastructure, AD REPLICATION -command is --repadmin /showrepl i just give you example suppose we have two server one is primary server and one is secondary server first we have to do make a one user in primary server and second we have to check replication partner it 's showing or not AD replication you can say gathering some information one to another .NTLM-Stand for network lan manager-he client is authenticating to a server using an IP address The client is authenticating to a server that belongs to a different Active Directory forest that has a legacy NTLM trust instead of a transitive inter-forest trust