404 error pages and 301 re-redirects
Many of us has come across this problem while surfing the website such as 404 Error – The page cannot be displayed error.What are these and why do they occur? Does these affect the search rankings? What needs to be done to avoid these? are few questions which may arise, when you come across such 404 Page Not Found Error.
Generally 404 – Page Not Found error are termed as “Broken Links”. These broken links occur, when there is a file missing in the root directory of the website, or the actual file name was which was working, has been renamed to something, will show as a broken link.
When it comes to search engine ranking, 404 definitely plays a role in it. More number of broken links in a website also leads to drop in the page ranks. For instance, you would do link building for certain pages and have acquired lot of external links, which provides a good value to you site. If you change the file name or remove the file in the web root directory, it would be a 404 error page. So this 404 error would reduce the traffic to the website, and also the chances of page rank drop is expected.
In order avoid such things the 404 – Page not found error webpage needs to be redirected to the right link or the new link, sometimes even to the homepage. These kind of redirects is termed as 301-Redirects. The redirect script should be wrote in the .htaccess file, which would be available as an hidden file in the website root directory. If that not available, you need to create one.
The 404-error page to a 301-redirect script is below. This needs to be added to the .htaccess file.
Options +Indexes
Options +FollowSymlinks
RewriteEngine on
RewriteBase /
RewriteRule ^index.htm$ http://www.your-domain-name.com/ [R=301,L]
The above script is valid for a specific i.e. single re-redirect only. In case of you need to redirect any 404 error pages to your home page, then you need to use the below rule.
RewriteRule ^whatever/[^.]+)$ http://www.your-domain-name.com/$1/ [R=301,L]
The above specified redirect script are required in the htacess to make 301 redirections, whereas if you want to redirect a www.example.com domain to www.example.co.in then you need to create a index.html file and add it to the root director of www.example.com. The simple re-direct html script required for that is
<html>
<head>
<meta http-equiv=”Content-Type” content=”text/html; charset=iso-8859-1″>
<meta name=”Description” content=”any description regarding your website “>
<meta http-equiv=”Refresh” content=”1; url=http://www.example.co.in /”>
<title>Example of HTML Re-redirect</title>
</head>
</html>
The above can be done in .htaccess as well.
Options +FollowSymLinks
RewriteEngine on
RewriteRule (.*) http://www.example.co.in/$1 [R=301,L]
The above redirects are also considered more imporant in Search Engine Optimizaiton. Hope this helps. Still have got questions, just post it in comments, we would surely reply you. 
. Soon this may also change. Coming back the point, here is how you can see how the spider looks into a website.
Day-to-day there are some changes that has been happening around web. So we Search Engine Optimizers need to be aware about all the recent happenings both the on-page optimisation techniques and off-page optimisation techniques to acquire top rankings in all major search engines, which inculde