whois c21school.edu.kh/kcfinder/themes/slotjoker.php

Domain:
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Try for webbased whois (don't expect it to work yet)
c21school.edu.kh/kcfinder/themes/slotjoker.php
checking....c21school.edu.kh/kcfinder/themes/slotjoker.php
   $ whois c21school.edu.kh/kcfinder/themes/slotjoker.php
No whois server is known for this kind of object.