1234689abcdefghiklmnopqrstuvwxyz
radio.scts.ru
random.mat.sbg.ac.at
rbnet.kstu-kai.ru
relay.qbix.ru
rene.ma.utexas.edu
ring.yamanashi.ac.jp
ringtail.its.monash.edu.au
romeo-klive.nvg.ntnu.no
root.cern.ch
rtfm.mit.edu