joomla site indexing problem some time face

[webrecsol]

hello guys,

I have joomla site and does the give some problem of Indexing then what should i do.

The problem is when I use the robots.txt file is left default like this

User-agent: *
Disallow: /administrator/
Disallow: /cache/
Disallow: /components/
Disallow: /images/
Disallow: /includes/
Disallow: /installation/
Disallow: /language/
Disallow: /libraries/
Disallow: /media/
Disallow: /modules/
Disallow: /plugins/
Disallow: /templates/
Disallow: /tmp/

then site is not indexed. but when i change the robots file to this

User-agent: *
Disallow: /administrator/
Disallow: /cache/
Disallow: /components/
Disallow: /images/
Disallow: /includes/
Disallow: /installation/
Disallow: /language/
Disallow: /libraries/
Disallow: /media/
Disallow: /modules/
Disallow: /plugins/
Disallow: /templates/
Disallow: /tmp/
Disallow: /xmlrpc/
Allow:/
then only the first page is indexed all the other pages are not !
why could this happen ?
can someone with me tell that what is the process of index...

[FLIR thermal imaging]

Thanks for sharing but I only know about off page work.