User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; de; rv:1.9.2.13) Gecko/20101122 Firefox/3.6.13 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; de; rv:1.9.2.13) Gecko/20101122 Firefox/3.6.13 Since some weeks it is possible to get German .de domains [1] containing the letter ß [2]. Firefox until now translates ß in the domain to ss and might lead you to a wrong page, if the owner of the domain did not register both versions. [1] http://www.denic.de/en/denic-in-dialogue/press-releases/press/2981.html [2] http://en.wikipedia.org/wiki/Eszet Reproducible: Always Steps to Reproduce: 1. Surf to http://groß.de 2. You end up at http://gross.de Actual Results: You might end up at the wrong page. Expected Results: groß.de and gross.de are not the same and might be bought by different people punycode [1] is a work around, but that doesn't help the average user other Mozilla products might suffer the same problem this whole thing might be used for phishing etc. [1] http://en.wikipedia.org/wiki/Punycode