DNS TTL and Propagation — Why DNS Changes Take Time

Описание: TTL is the Time to Live — how long DNS resolvers are allowed to cache your record. Set it too high and your changes take 48 hours to propagate. Set it too low and every request hits your nameserver. The right strategy before and after a migration.

📂 Module 5: DNS Basics — The Internet's Phonebook
🎓 Course: Deploy Like a Pro

⏱ Timestamps:
00:00 Introduction
00:30 What TTL means
01:30 How caching works at each resolver layer
03:00 Why 48-hour propagation happens
04:30 Pre-migration TTL strategy (lower before migrating)
06:00 Post-migration: when to raise TTL back

#dns #ttl #dnspropagation #caching #networking #devops #domainmigration