For advanced websites. This plugin primarily allows you to redirect URLs and log 404 “Page Not Found” errors. You can preserve traffic going to pages or posts you have renamed or deleted. The log will help you find lost traffic, so you can set redirects for future visits to those URLs. To activate this plugin, go to the Plugins menu, find Redirection, and click Activate. To use this plugin, go to the menu Tools > Redirection.
Important: The Redirection plugin is for advanced users and can cause inadvertent redirects if it is not properly configured.
The main submenus for the Redirection menu are shown across the top – Redirects, Groups, Modules, Log, Options, and Support.
The redirects are organized into groups, and each group is part of a module. When you go to the Tools > Redirection menu, the default group, Redirections, is shown. The Redirections group is part of the WordPress module. You will probably only need to use this group when adding and editing redirects.
Adding Redirects
To add a new redirect, you need to go to the appropriate group you want to add the redirect to. At the bottom of the page, there is a section called “Add new redirection.” The Source URL is the URL that you want people to be redirected away from. The Target URL is the URL that you want people to end up at if they try to go to the Source URL.
Match options. In most cases you will use the default, “URL only.” The other options will restrict the redirect based on other conditions – referrer, user agent, and login status. Unless you are an advanced user you will probably never use these options.
Action options. In most cases you will use the default, “Redirect to URL.” The other options are “Redirect to random post,” “Pass-through,” “Error (404),” and “Do nothing.” You might use the “Do nothing” option for a URL that is triggering 404 errors, and you don’t want to change it but you also don’t want it to show up in the log.
Regular expression. If you check this box, the redirect will process regular expressions. A regular expression is written in code and it is used to dynamically match text. For example, you may write a regular expression to match all URLs that match a certain subdirectory, such as http://example.com/deletedsubdirectory/page1, http://example.com/deletedsubdirectory/page2, http://example.com/deletedsubdirectory/anotherdeletedsubdirectory/page3. In that example, you could write a single regular expression to point all of those URLs (and any others that begin with http://example.com/deletedsubdirectory/) to a single new URL.
Reference websites for regular expressions:
Editing Redirects
Click on the redirect to edit it. You can title the redirect so it’s easier to identify. The title has no effect on what the redirect does. You can also change the Source URL, Target URL, HTTP Code (always use the default “301 – Moved Permanently” unless you understand the effects of the other status codes), and toggle Regex (regular expressions). If you want to change the Match or Action options, you will need to delete the redirect and create a new one with the options you want.
Deleting Redirects
To delete one or more redirects, check the boxes next to those redirects. If you started editing one of the redirects, you need to click Save or Cancel in order to get the checkbox to reappear. Then click the Delete link in the lower right.
404 Errors Log
To view the 404 Errors log, you will need to click the Modules link, then find the row for 404 Errors, and click the number in the Hits column. If you click the Log link, you will see the log for the current module. This is the WordPress module by default.
You may see a lot of unusual entries. These are often caused by automated bots visiting your website, “scraping” information or trying to find ways to hack in. Unfortunately, this is normal if your website is public. However, if you recognize old page or post names, you should consider redirecting those URLs. If you click on the URL, you will go to that URL (and you should see a 404 error). You can simply click the green + icon to the far right of the log entry to add a redirect for that URL.
Recommended Settings
Go to the Tools > Redirection menu, go to the Options page, go to “Post & Page URLs,” and select “Don’t monitor.” There is a bug that will sometimes cause your home page to redirect to newly created posts or pages.
Go to the Tools > Redirection menu, go to the Options page, go to “Expire Logs,” and change the value from “0″ to “90″. If the logs are not set to expire, they can build up over time and slow down your site performance.
For more information, see the plugin page(s):
http://wordpress.org/extend/plugins/redirection/