Internet name server systems can only process the traditional letters (a to z) of the Latin alphabet. In order for name servers to accept native language characters in domain names, the characters must be converted into another form.
Software, internet browsers and email programs that support national domain names automatically convert them from plain text into a form that name server systems can read.
However, due to technical restrictions, it is not recommended to use a domain name containing native language characters as a primary domain name.
Permitted characters in domain names
The permitted characters in fi-domain names are letters from a to z, numbers from 0 to 9, hyphen-minus and the following native language characters:
An fi-domain name cannot begin or end with a hyphen-minus. A domain name cannot begin with characters xn--. The ACE form (ASCII Compatible Encoding) of a domain name containing native language characters always begins with characters xn--.
Rights to domain names containing native language characters
Fi-domain name holders have no priority to a domain name similar to their domain name apart from native language characters (å, ä, ö). These domain names, too, are granted on a first-come, first-served basis.
However, regardless of whether a domain name contains native language characters or not, it can be considered identical to a protected name or trademark that contains native language characters.
For example, both domain name åäö.fi and domain name aao.fi would be considered identical to the protected name or trademark ÅÄÖ. Instead, if the protected name or trademark were AAO, the only domain name considered identical to it would be aao.fi.
An IDN converter converts a domain name that is in plain text or contains special characters into punycode.
A domain name is always entered as punycode in the domain name system. For example, the punycode form of the domain name viestintävirasto.fi is xn--viestintvirasto-7kb.fi.
IDN converter allows you to see the punycode form of your domain name even before you apply for the domain name.
Technical restrictions of browser software
The latest versions of most browser software support domain names containing native language characters. The most popular of them are Mozilla Firefox, Microsoft Internet Explorer, Microsoft Edge, Google Chrome and Safari.
Technical restrictions of email addresses
If domain names containing native language characters are intended to be used in email addresses, the sender's email program must support such characters. The support in many email programs is still insufficient, and therefore it is recommended to check this directly from the manufacturer of the program.
Due to technical restrictions, it is not recommended to use a domain name containing native language characters in an email address. Few email programs support IDNs. Without IDN support, the domain name has to be used in an impractical coded form. For example, info@ääkkönen.fi in coded form is info@ xn--kknen-fraa=0m.fi.
Keyboard support for native language characters
It can be difficult or even impossible to type fi-domain names containing native language characters using a foreign language keyboard. Without keyboard support, one solution for entering native language characters in Windows operating system is Character Map program.