Data::Validate::Domain->new()

• domain_allow_underscore

  According to RFC underscores are forbidden in hostnames but not domain names. By default "is_domain()", "is_domain_label()", and "is_hostname()" will fail if the value to be checked includes underscores. Setting this to a true value will allow the use of underscores in all functions.

• domain_allow_single_label

  By default "is_domain()" will fail if you ask it to verify a domain that only has a single label i.e. "neely.cx" is good, but "com" would fail. If you set this option to a true value then "is_domain()" will allow single label domains through. This is most likely to be useful in combination with the "domain_private_tld" argument.

• domain_disable_tld_validation

  Disables TLD validation for "is_domain()". This may be useful if you need to check domains with new gTLDs that have not yet been added to Net::Domain::TLD.

• domain_private_tld

  By default "is_domain()" requires all domains to have a valid public TLD (i.e. com, net, org, uk, etc). This is verified using the Net::Domain::TLD module. This behavior can be extended in two different ways. You can provide either a hash reference where additional TLDs are keys or you can supply a regular expression.

  NOTE: The TLD is normalized to the lower case form prior to the check being done. This is done only for the TLD check, and does not alter the output in any way.

  Hashref example:

    domain_private_tld => {
        privatetld1 => 1,
        privatetld2 => 1,
    }
      

  Regular expression example:

   domain_private_tld => qr /^(?:privatetld1|privatetld2)$/,
      

is_domain($domain, \%options)

This returns the untainted domain name if the given $domain is a valid domain.

A dotted quad (such as 127.0.0.1) is not considered a domain and will return false. See Data::Validate::IP for IP Validation.

Per RFC 1035, this sub does accept a value ending in a single period (i.e. "domain.com.") to be a valid domain. This is called an absolute domain name, and should be properly resolved by any DNS tool (tested with "dig", "ssh", and Net::DNS).

From RFC 952

   A "name" (Net, Host, Gateway, or Domain name) is a text string up
   to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus
   sign (-), and period (.). Note that periods are only allowed when
   they serve to delimit components of "domain style names".

   No blank or space characters are permitted as part of a
   name. No distinction is made between upper and lower case. The first
   character must be an alpha character [Relaxed in RFC 1123] . The last
   character must not be a minus sign or period.
    

From RFC 1035

    labels          63 octets or less
    names           255 octets or less

    [snip] limit the label to 63 octets or less.

    To simplify implementations, the total length of a domain name (i.e.,
    label octets and label length octets) is restricted to 255 octets or
    less.
    

From RFC 1123

    One aspect of host name syntax is hereby changed: the
    restriction on the first character is relaxed to allow either a
    letter or a digit. Host software MUST support this more liberal
    syntax.

    Host software MUST handle host names of up to 63 characters and
    SHOULD handle host names of up to 255 characters.
    

is_hostname($hostname, \%options)

This returns the untainted hostname if the given $hostname is a valid hostname.

Hostnames are not required to end in a valid TLD.

is_domain_label($label, \%options)

This returns the untainted label if the given $label is a valid label.

A domain label is simply a single piece of a domain or hostname. For example, the "www.foo.com" hostname contains the labels "www", "foo", and "com".