How Google Handle 301 and 302 Redirects to Manage Indexing and Page Rank

Many people get confused about the SEO factors of 301 and 302 redirects. It is important to know how Google handle 301 and 302 redirects, how it passes link juice and page rank based on redirects and the indexing of the source and destination URLs.   In this article let us try to understand how Google handle these redirects and how that influences indexing of pages, passing link juice from source and destination URLs and the page rank transfer.  We will also understand the SEO factors of these HTTP redirects.
URL redirection can be used in different scenarios such as

• URL shortening
• To prevent broken links when web pages are moved to a different location
• To redirect multiple domain names that belongs to same owner to a single web site.
• URL redirection can also be use to guide navigation into and out of a website.
• URL redirection also abused by hackers and virus programs to launch phishing attacks using URLs that are similar to a targeted web site.

Related Articles:

• Affiliate Link Redirects and Google Webmaster Guidelines
• How to Create WordPress PHP Affiliate Jump Script
• WordPress Permalink Change, htaccess 301 Redirect and Subdomain
• Website or Web page redirection using a .htaccess file?

301 redirect or the HTTP 301 status code indicates permanent location change. 301 redirection is used for permanent redirection. Google recommends using a 301 redirect if you need to change the URL of a page as it is shown in search engine results.You can edit the .htaccess file of the apache web server to implement a 301 redirect for websites.
302 redirects are temporary redirect, and HTTP 302 status code means that a page has temporarily moved to a new location.(HTTP/1.1 added status codes 303 and 307 where 303 is virtually equal to 303 because popular browsers implemented 302 redirects as a 303 “See Other“)

301 and 302 Redirects and How Google Indexes URLs

As we discussed 301 status code means that a page has permanently moved to a new location. So Google will index the new URL by replacing the old one.
302 redirects can be on-domain or off-domain. On-domain 302 redirects are a redirect in which both the source page and the destination page are both on the same domain. As Matt Cutts suggested in his 2006 blog post (I believe it is still valid)
“An on-domain 302 shouldn’t hurt a site, but if you’ve moved everything to a new location for good, I’d try using a 301 (permanent) redirect instead.”

301 and 302 Redirects and How Google Passes Link Juice and Page Rank

If you use a 301 Redirect then the link juice and page rank will get transferred to the redirected page. This is because Google consider it as a permanent redirection.
302 redirects typically don’t pass PageRank because it is a temporary redirect. But having said that if you use a 302 which typically doesn’t pass PageRank and add a nofollow link attribute will ensure that it doesn’t pass Page Rank and link juice to the redirected domain. Similarly if you use a 301 which does pass PageRank and if you add a nofollow, it doesn’t pass Page Rank to the redirected page. This is because the search engine spiders respect the rel=”nofollow” link attribute.