Finding things.
WHAT AN ADDRESS IS
A number identifying a device on a network.
WHAT THE TWO VERSIONS ARE
The older form, which has run out The newer form, providing enough for every device
WHAT A DOMAIN NAME IS
A readable name, translated to an address.
HOW TRANSLATION WORKS
Your device asks a resolver The resolver asks the authoritative servers for that name The answer returns and is cached
WHAT CACHING CAUSES
Changes not appearing immediately, and appearing at different times for different people.
WHAT PROPAGATION ACTUALLY IS
Caches expiring, not a spreading process.
WHAT THE COMMON RECORD TYPES DO
Point a name at an address Point a name at another name Direct mail for a domain Hold text, used for verification and mail authentication Declare which servers are authoritative
WHAT BREAKS MOST OFTEN
Records added where the nameservers do not point.
WHAT TO CHECK WHEN A SITE DOES NOT RESOLVE
What it resolves to, from more than one resolver.
