IDN Module

The idn (Internationalised domain names) encoding for DNS aka IDNA standardized in RFC 3490.

The expansion string: %idn(example.com) results in an ASCII punycode version of the domain name. That version can then be used for name comparisons. Using an i18n version of the name is NOT RECOMMENDED, as that version is not canonical.

i.e. the same domain name can be represented in many, many, different ways. Only the idn version has one representation.

Configuration Settings

allow_unassigned: Allow use of unassigned Unicode code points.
use_std3_ascii_rules: Prohibit underscores and other invalid characters in domain names.

Default Configuration

idn {
	allow_unassigned = no
	use_std3_ascii_rules = yes
}