Same page, different URLs

[AlphaWarrior]

Because the home/index page can be accessed by both
http://www. domain.com and http:// domain.com (without the www) it can be considered duplicate content. Not good for seo and needs a redirect from one to the other.

Question: Does the principle also apply to pages?
Is http://www. domain.com/keyphrase-page.html the same as
http:// domain.com/keyphrase-page.html (without the www)? If the principle is the same for the home/index page and all other pages, should each page have a redirect also or is there a way to have all pages redirected to either the www version or non-www version?

My website was made using html, not wordpress or any other program with a plugin.

Thanks.

[ellenpage]

You should edit .htaccess at your website with code below, all pages will redirect from non www to www verison

RewriteCond %{HTTP_HOST} ^domain.com$ [NC]
RewriteRule ^(.*) http://www.domain.com/$1 [L,R=301]

My website is html too (vietnamtravelkey.com)

[Matt Baker]

Originally Posted by ellenpage

You should edit .htaccess at your website with code below, all pages will redirect from non www to www verison

RewriteCond %{HTTP_HOST} ^domain.com$ [NC]
RewriteRule ^(.*) http://www.domain.com/$1 [L,R=301]

My website is html too (vietnamtravelkey.com)

This is the best solution for you AlphaWarrior.

[ConnerHogan]

Why does the "www" make it separate content?

[AlphaWarrior]

Originally Posted by ConnerHogan

Why does the "www" make it separate content?

I do not know why, but with the home/index/main page, search engines look at the following 6 variations as 6 different pages even though all of the variations go to the same page. Because search engines look at them as 6 pages with identical content on the same domain, it can cause duplicate content issues.

http://www. domain.com (with www, but no slash)
http://www. domain.com/ (with www and a slash
http:// domain.com (without www and without a slash)
http:// domain.com/ (without www, but with a slash)
http://www. domain.com/index.html
http:// domain.com/index.html

What I don't know is whether or not the same variation principle carries over to interior pages. Apparently it can, and both Matt and ellenpage recommend modifying the .htaccess file.

Thanks ellenpage and Matt.

[ellenpage]

@ConnerHogan: Because Google say :

If you don't specify a preferred domain, we may treat the www and non-www versions of the domain as separate references to separate pages.

[amherstsowell]

Both are different thing Welcome to Home.com or (home.com/index), when we open both pages its show same content because we have need to index file for run the site so that's why we change the website home page with index or our domain exist (domain.com) on the both pages its come same but google treat different. its wrong because everything is same on the both pages (Home.com) or (home.com/index.html) but on another pages of website we add different content on every pages.