N3M Technical
Names and addresses
DNS maps readable names to network addresses. Resolvers cache answers for the time specified by each record's TTL, so changes may take time to reach every network.
Keeping copies
A useful backup is one you can restore. Keep an independent copy of important files and occasionally check that the recovery procedure works.
Small, repeatable steps
Record the starting point, make one change at a time, and verify the result. Clear notes make later maintenance easier.