How to Setup Canonical Domain Names with Apache Nov 26, 2009, 23 :04 UTC (0 Talkback[s]) (6211 reads) (Other stories by Sukrit Dhandhania)
"Using canonical URLs you can merge all of these so that your web server treats them all the same in a web browser. This has a positive impact on search engine optimization. Not using canonical URLs has a negative impact on your SEO, as Google notices that several URLs are returning the same content and penalizes you.
"Canonical domain name is the full form of CNAME. You might have encountered this term while setting up your domain name. CNAME is an entry, which is a part of your domain's DNS records. A computer hosting a website has an IP address, which is used to access the content over the web. DNS helps us avoid distributing numeric IP addresses to people and handles the conversion from domain names to IP addresses. This is pretty straightforward when you have one website being served by an IP address. However, you might want to serve various websites with the same IP address and the same domain name. This can be done using subdomains such as forums.sevenacross. The subdomains are handled by the domain's CNAME records."
