| ALabel | 
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| DnsLabel | 
 A DNS label is an individual component of a DNS name. 
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| FakeALabel | 
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| LdhLabel | 
 A LDH (Letters, Digits, Hyphen) label, which is the classical label form. 
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| LeadingOrTrailingHyphenLabel | 
 A DNS label with a leading or trailing hyphen ('-'). 
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| NonLdhLabel | 
 A DNS label which contains more than just letters, digits and a hyphen. 
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| NonReservedLdhLabel | 
 A Non-Reserved LDH label (NR-LDH label), which do not have "--" in the third and fourth position. 
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| OtherNonLdhLabel | 
 A Non-LDH label which does not begin with an underscore ('_'), hyphen ('-') or ends with an hyphen. 
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| ReservedLdhLabel | 
 A reserved LDH label (R-LDH label), which have the property that they contain "--" in the third and fourth characters. 
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| UnderscoreLabel | 
 A DNS label which begins with an underscore ('_'). 
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| XnLabel | 
 A label that begins with "xn--" and follows the LDH rule. 
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