I'm trying to code my sites mobile version. it will be like this: www.example.com => mobile.example.com
im using this alternate tag in desktop page; thats ok:
<link rel="alternate" media="only screen and (max-width: 800px)" href="http://mobile.example.com/first_link.html">
and using this canonical tag in mobile version; thats ok too:
<link rel="canonical" href="http://www.example.com/first_link.html" />
now.. should i also ban the mobile pages via robots.txt file? (by adding robots.txt file to the root of mobile directory; with Disallow: / line)
because if not, google will index both www. and mobile. url's.. (all contents are the same; the only difference is: design)...
what sould i do? using canonical/alternate tags will be enough to no-indexing? or should i also use robots.txt to disallow mobile directory?