RewriteCond %{HTTP_HOST} ^(.*)\.renbo\.net$ [NC]
RewriteCond %{REQUEST_URI} ^/([^/]+)/ [NC]
RewriteCond %1 !%2
RewriteRule ^(.+)$ http://%1.renbo.net/ [L]

147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (2) init rewrite engine with requested uri /xxx/
147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (3) applying pattern '^(.+)$' to uri '/xxx/'
147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (4) RewriteCond: input='xxx.renbo.net' pattern='^(.*)\.renbo\.net$' => matched
147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (4) RewriteCond: input='/xxx/' pattern='^/([^/]+)/' => matched
147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (4) RewriteCond: input='xxx' pattern='!%2' => matched
147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (2) rewrite /xxx/ -> http://xxx.renbo.net/
147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (2) implicitly forcing redirect (rc=302) with http://xxx.renbo.net/
147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (1) escaping http://xxx.renbo.net/ for redirect
147.10.187.222 - - [29/Jun/2006:18:10:12 +1000] [xxx.renbo.net/sid#814f530][rid#a6d7490/initial] (1) redirect to http://xxx.renbo.net/ [REDIRECT/302]