xn--mller-kva.de = müller.de
The new characters have to be converted first. In case a domain contains a "non"-ASCII sign (ä,ö,ü etc.) it has to be converted into an ASCII string.
This conversion happens through the Punycode-algorithm that creates an ACE string.
"xn--" "ASCII-sign" "-" "Punycode".de
For müller.de the result is: xn--mller-kva.de
The addition "kva" contains the information about the umlaut (ü) in the domain name.
In order to read umlaut domains the Internet Explorer needs a plugin. The free plugin from VeriSign is available here and is suitable for the operating systems Win 98, ME, NT, 2000 and XP (from IE 5.0 on).
The browsers Opera (from version 7.2 on), Mozilla (from version 1.5 on) and Netscape (from version 7.1 on) are able to resolve the new domains.
If you are planning to send eMails with Outlook or Outlook Express (from verison 5.0 on) using IDNs you will need the plugins "i-NavOutlook" and "i-NavOE". These free plugins from VeriSign are available here.