An FQDN, or Fully Qualified Domain Name, is a computer's complete name in the format of hostname.domain.tld. It is crucial in the DNS hierarchy, aiding in the identification of objects like hosts in Active Directory without requiring their IP addresses. For example, the FQDN for the hostname DC01 in the domain SEMO.LOCAL would be DC01.SEMO.LOCAL.
A tombstone in Active Directory is a container object that holds deleted objects for a period known as the tombstone lifetime, during which the isDeleted attribute is set to TRUE.
After this period, the object is permanently removed. The default tombstone lifetime is either 60 or 180 days, depending on the domain controller's OS version.
Without the AD Recycle Bin, deleted objects become tombstones and lose some attributes, which cannot be restored once the tombstone lifetime expires.
The AD Recycle Bin, introduced in Windows Server 2008 R2, allows for the recovery of deleted AD objects without the need for backups, AD DS restarts, or DC reboots. It stores deleted objects for a default recovery period of 60 days, preserving most attributes to facilitate full object restoration.
SYSVOL, or system volume, is a repository for public files like policies, Group Policy settings, and scripts within an Active Directory domain, which are replicated across all domain controllers using the File Replication Service (FRS).
The FRS ensures consistent distribution of these files among all domain controllers. The Knowledge Consistency Checker (KCC) manages the replication topology between domain controllers, ensuring efficient and reliable replication of directory information across the Active Directory infrastructure.
Summary:
- An FQDN is a computer's full name used in DNS to identify objects like hosts in Active Directory without their IP addresses.
- The AD Recycle Bin allows recovery of deleted objects while preserving most attributes
- SYSVOL holds and replicates public files like Group Policy settings across domain controllers using FRS.