.htaccess - set a subdomain with redirect to the index page -

i have domain abdefg.it.

i have set subdomain sub.abcdefg.it pointing in directory contain:

index.php foldera .htaccess 

the problem if type url sub.abcdefg.it error appear, if type sub.abcdefg.it/index.php goes well.

that contained in .htaccess file

rewriteengine on  rewritecond %{http_host} ^sub\.abcdefg\.it$ [or] rewritecond %{http_host} ^www\.sub\.abcdefg\.it$ rewriterule ^/?$ "http\:\/\/www\.abcdefg\.it\/sub\/index\.php" [r=301,l] 

what doing wrong?

thanks you.

you can that:

rewriteengine on rewritecond %{http_host} ^(?:www\.)?sub\.abcdefg\.it$ rewriterule .* http://www.abcdefg.it/sub/index.php [r=301,l] 

now, redirect http_host.

before work well, use [r=302,l] tests, without cache.