On the 11th of September 2003 NASK released domain names with the "xn--" prefix for registration in .PL zone and on the 18th of September 2003 for the second level domains, serviced by NASK.
Domain name with the "xn--" prefix must be prepared in accordance with IETFs documents i.e. RFC 3490, RFC 3491, RFC 3492 in order to be registered.
Domain name with the "xn--" prefix, submitted for registration, after it has been transformed into the unicode form, can include merely code points from one of the sets, defined in allowed_character_sets.pdf document. Combination of characters from different sets is not allowed.
Domain name with the "xn--" prefix, represented by ASCII code, is registered in accordance with the IDNA standard (RFC 3490). NASK shall not be held responsible for consequences of common adoption of international standard different than standard used on the day of particular domain name registration. If you register a domain name in ASCII code, with the "xn--" prefix, you agree to benefit from the service provided by NASK, subject to a condition mentioned in the previous sentence.