forked from pifty/tutes-dump
43 lines
1.7 KiB
Plaintext
Executable File
43 lines
1.7 KiB
Plaintext
Executable File
[02] WHAT ARE THE DIFFERENT DNS RECORD TYPES?
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This is a pretty quick and basic description. The most
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important records are the A, MX and CNAME. You can probably
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figure out how the DNS database entry works.
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SOA Start Of Authority. Is probably the most complicated
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portion of the DNS database to understand. SDF takes
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care of this record for you.
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A Address record. The IP address for a host or domain.
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MX Mail Exchanger. The host who handles mail for your
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domain/hosts. There is a numeric value before the
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MX host to specify preference (typically 75 for
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a primary, and 100 for a secondary)
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CNAME Canonical Name - an equivilent host name.
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A typical database (without the SOA) might look like this:
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$ORIGIN mydomain.org.
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foo IN A 10.0.0.1
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IN MX 75 foo.mydomain.org.
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IN MX 100 mail.anotherhost.org.
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bar IN CNAME foo.mydomain.org.
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Notice that the "." at the end of text is of importance.
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the $ORIGIN is a tag in the database, which tells the nameserver
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that all information following needs to have 'mydomain.org.'
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appended to the initial tag (id est, foo.mydomain.org. instead
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of just 'foo').
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In the above example, host 'foo' has an address of 10.0.0.1 and
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its favourite mail exchanger is itself. In the event that it
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is unavailable, its second favourite mail exchanger is
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'mail.anotherhost.org' which lives outside of this database.
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Host 'bar' in basically just an equivilent name for 'foo' .. although
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you could of just had another A and MX records for 'bar', this is
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the most efficient and clean way to build your database.
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