I have a question if i have same page with three different urls names like www.xyz.com/ www.xyz.com/index.php www.xyz.com/index1.php Is this content duplicacy?
yes if you have been using same content all over then "G" may certainly consider it as duplicate.You may apply 301 redirect so that Google may know that all are being redirected with no duplication.
Yes..it makes problems. Google need unique contents. So different urls with same content is not permitted