Most organizations hate DNS and hate to see it done properly. That is why they buy enterprise DNS management kludge and do not allow correct hierarchical subdomains.
Once I did run a proper DNS server. Unfortunately I left my original notes from 2006 back with the people for whom I managed it. Here are some minor note on the topic.
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A = IPv4 address record
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AAAA = IPv6 address record
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CNAME = Canonical Name, basically an alias. DNS continues trying the lookup with the new name.
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DNAME = Like CNAME but alias for entire domains and subdomains.
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PTR = Pointer record. Like CNAME but processing stops. SOA = Start of Authority. Where to find the most true information.
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MX = mail exchange
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TXT = Could be a message for humans. Could be something else.
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NS = nameserver record, points to a different resource for finding
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subdomains names for this domain.
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SSHFP = SSH host key fingerprints to help with this problem.
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SPF = Sender policy framework - OBSOLETE