Regular Expressions 101

Library entries

DNS hostname well-formedness validation

Vote

3

Regular Expression
pcre

/
^(?:_?(?>[a-z\d][a-z\d-]{0,61}[a-z\d]|[a-z\d])\.)*(?:_?(?>[a-z\d][a-z\d-]{0,61}[a-z\d]|[a-z\d]))\.?$
/
i

Description

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Submitted by Jeff Walter - 5 years ago