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domain.doc
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1991-06-26
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3KB
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100 lines
by Mike Bilow, N1BEE
June 25, 1991
Here are the basic translation rules which are employed by GRINOS for
resolving a hostname to an IP address. These examples all assume that
a domain suffix (ampr.org.) has been set up.
The basic rule is the same as in G1EMM NOS (KH113016) and its derivatives.
1. If a name is supplied without a dot in it, the domain suffix is appended:
Search request: n1bee
Translates to: n1bee.ampr.org.
Match record: n1bee.ampr.org. IN A 44.104.0.20
In G1EMM NOS, names with dots will never have the domain suffix appended.
GRINOS adds two cases where the domain suffix can be appended, depending
upon where the last dot is found and what follows it.
2. If a name is supplied with a dot in it, and there are more than four
characters following the last dot, the domain suffix is appended:
Search request: switch.w1cg-9
Translates to: switch.w1cg-9.ampr.org.
Match record: switch.w1cg-9.ampr.org. IN A 44.104.0.2
3. If a name is supplied with a dot in it, there are four or less characters
following the last dot, and one of the characters following the last dot is a
numeral, the domain suffix is appended:
Search request: balrog.k8lt
Translates to: balrog.k8lt.ampr.org.
Match record: balrog.k8lt.ampr.org. IN A 44.52.0.17
In all other cases, the domain suffix will not be appended. This forces
the use of special rules within the DOMAIN.TXT file. In particular, names
which are like the above but have a trailing dot left in them must be handled
separately with a PTR or CNAME record type that initiates another search:
Search request: switch.w1cg-9.
Translates to: switch.w1cg-9.
Match record: switch.w1cg-9. IN CNAME switch.w1cg-9.ampr.org.
Search request: switch.w1cg-9.ampr.org.
Translates to: switch.w1cg-9.ampr.org.
Match record: switch.w1cg-9.ampr.org. IN A 44.104.0.2
The above rules handle most cases that will be encountered, but they also
imply that certain hostnames require canonical name records:
Search request: kc2fd.sl
Translates to: kc2fd.sl.
Match record: kc2fd.sl. IN CNAME kc2fd.sl.ampr.org.
Search request: kc2fd.sl.ampr.org.
Translates to: kc2fd.sl.ampr.org.
Match record: kc2fd.sl.ampr.org. IN A 44.68.8.57
A few things that have been all right until now should be fixed up.
1. A number of entries in the DOMAIN.TXT files that can no longer be matched
unless fully qualified should have CNAME records inserted:
Search request: poli.nyli
Translates to: poli.nyli.
Match record: (none)
Intended record: poli.nyli.ampr.org. IN A 44.68.16.1
2. All type A (address) records should be fully qualified or they cannot be
matched at all:
Search request: w2jup
Translates to: w2jup.ampr.org.
Match record: (none)
Intended record: w2jup. IN A 44.68.8.99
3. All null host A and null address CNAME records should be removed, as
they serve no function and can cause incorrect address resolution.
Search request: kb2kmy2
Translates to: kb2kmy2.ampr.org.
Match record: kb2kmy2.ampr.org. IN CNAME .
Search request: .
Translates to: .
Match record: . IN A 44.56.4.48
Intended record: kb2kmy2.ampr.org. IN A 44.68.64.165