Scenario
You
are upgrading your website and as part of the upgrade,
it means moving and renaming particular files.
Danger
Search
engines have indexed your entire site and many pages
rank well. By moving and renaming these files, you run
the risk of losing a lot of traffic and leaving visitors
to your site who follow a search engine link with the
dreaded "Error 404 - File not found"
Strategy
1 - Custom Error Page
You
could create a custom error page . The problem with
this solution is that:
a) You will lose rankings on the next search engine
update as the file will appear to be non-existent. It
could be some time before the page in it's new location
or with a new name reappears.
b) Your website visitors may be frustrated by the fact
that they then have to dig through your site to find
the desired information.
Strategy
2 - Meta Refresh
A
meta refresh can be implemented in the statement of
your source code in blank page with the old file name,
which then automatically redirects visitors to the new
page. Example:
<HEAD>
< META HTTP-EQUIV="refresh" content="0;URL=http://www.new-url.com/new.htm">
<TITLE>Page has moved</TITLE>
</HEAD>
Warning:
This is a technique often used by spammers to trick
search engines and it should be avoided, unless the
page is in a section of your site that isn't spidered.
What the search engine spammers do is to create a page
that is optimized for certain keywords and phrases -
it usually has no real content. The page is then picked
up by some search engines, but when a visitor clicks
on the search engine entry, they are redirected to another
site, often unrelated.
It's a despicable trick, but thankfully most search
engines have filters to detect this. Using this form
of SE deception will see a site eventually banned or
penalized by major players such as Google.
Strategy
3 - HTTP 301 Redirect in PHP
<?
Header( "HTTP/1.1 301 Moved Permanently" );
Header( "Location: http://www.domain.com" );
?>
OR
<?php
// Permanent redirection
header("HTTP/1.1 301 Moved Permanently");
header("Location: http://www.domain.com/");
exit();
?>
If you set the Location header by itself, PHP automatically
sets the status code to HTTP/1.1 302 Found.
Note: If you attempt to send headers
after content has been sent, you will get a warning
like, "Warning: Cannot modify header information - headers
already sent by ...". Watch out for empty lines and
spaces between PHP open and close tags. ASP ignores
these, but PHP does not.
Strategy
4 - 301 Redirect with .htaccess
A
301 redirect is the most efficient and spider/visitor
friendly strategy around for websites that are hosted
on servers running Apache (check with your hosting service
if you aren't sure). It's not that hard to implement
and it should preserve your search engine rankings for
that particular page. If you *have* to change file names
or move pages around, it's the safest option.
A 301 redirect is implemented in your .htaccess file.
What is a .htaccess file?
When a visitor/spider requests a web page via any means,
your web server checks for a .htaccess file. The .htaccess
file contains specific instructions for certain requests,
including security, redirection issues and how to handle
certain errors.
What is a 301 redirect?
The code "301" is interpreted as "moved permanently".
After the code, the URL of the missing or renamed page
is noted, followed by a space, then followed by the
new location or file name
How do I implement a 301 redirect?
First of all, you'll need to download the .htaccess
file in the root directory of where all your web pages
are stored. If there is no .htaccess file there, you
can create one with Notepad or a similar application.
Make sure when you name the file that you remember to
put the "." at the beginning of the file name. This
file has no tail extension.
If there is a .htaccess file already in existence with
lines of code present, be very careful not to change
any existing line unless you are familiar with the functions
of the file.
Scroll down past all the existing code, leave a line
space, then create a new line that follows this example:
redirect 301 /old/old.htm http://www.you.com/new.htm
It's as easy as that. Save the file, upload it back
into your web and test it out by typing in the old address
to the page you've changed. You should be instantly
and seamlessly transported to the new location.
Notes: Be sure not to add "http://www" to the first
part of the statement - just put the path from the top
level of your site to the page. Also ensure that you
leave a single space between these elements:
redirect 301 (the instruction that the page has moved)
/old/old.htm (the original folder path and file name)
http://www.you.com/new.htm (new path and file name)
A more powerful set of directives for manipulating URLs
is contained in the Apache mod_rewrite module, especially
useful when changing domain names and/or folder names
containing large numbers of files. Read our basic tutorial
on the apache
mod_rewrite module.
Redirecting entire sites with 301
The 301 directive is quite powerful. You can redirect
not just single files but entire sites, for example
when changing domain names e.g.
redirect 301 / http://www.you.com/
The first "/" indicates that everything from the top
level of the site down should be redirected. As long
as you are using the same paths and filenames, then
this option is a very simple way to perform site redirection
in the situation where you have only changed your domain
name.
Search engine spiders & 301 redirects
The 301 redirect is the safest way to preserve your
rankings. On the next spidering, the search engine robot
will obey the rule indicated in your .htaccess file.
The search engine spider doesn't actually read the .htaccess
file, but recognizes the response from the server as
valid.
In the next update, the old file name and path *should*
be dropped and replaced with the new one. Sometimes
you may see alternating old/new file names during the
transition period, along with some possible fluctuations
in rankings as things settle. Don't panic - this is
normal and may take a number of weeks before everything
is back to normal; but the bottom line is, any change
you make has risks - whether it's altering page text,
moving/renaming pages or changing domain names. Search
engines run by their own rules and can change those
rules at any time.
If you're changing domain names and using a 301 redirect,
you'll need to leave the old domain name and files in
place for a few weeks to give the major search engines
time to catch on to the changes and don't forget to
notify your link partners of the domain name change
as soon as possible. Once you deactivate the old domain,
any search engine kudos you've built up through those
links will be gone.
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