Redirect non www. domain to WWW. domain for established website?

[BruLee]

Hey guys,

The website in question has been online for more than 5 years but there are still 2 versions of the website. Both versions are indexed by Google and of course, this will result in duplicate content.

Is it necessary to redirect the non-www domain to the www. domain. What are the cons and advantages?

Will a lot of organic traffic be lost at first (if non-www are getting a good amount of traffic)?

Thanks.

[SEO5Team]

stand corrected, what i meant was to set the preferred domain on GWT and do the 301 via the servers. Thanks for pointing that out Keri.

[KeriMorgret]

SEO5, can you add some more information about how to use Google Webmaster Tools to do a 301 redirect for URLs? I'm not sure that this is possible. 301s usually require server access, and GWT doesn't control your server. You can set your preferred domain in GWT, but you would still want to do a 301 for users and for other search engines.

[SEO5Team]

If you do a 301 redirect from one URL to the other using Google Webmaster Tools, you should be ok. Try to do the 301 to specific pages that relate to the content on the main site.  You may see a dip in traffic however over time that should recover.