How to recover DNS if someone deletes it by mistake ?
Presuming we are talking about ONE or a FEW zones,
otherwise it's pretty much from backup:
From backup. From a secondary. Files on disk. Manually.
If you have replicated, then the secondary method won't
work.
If you lose the Primary, you can just make a secondary the
Primary (temporarily) and reverse the replication direction.
Works with AD Integrated too (and the method here works
for AD integrated the same as a Primary except that deleting
records on ONE AD-integrated removes them from all just
like the Primary-Secondary.)
Check all DNS servers for the zone to see if there is a (useful)
copy of the zone in your DNS directory (usually under System32).
Backup or type them back into the server.