You worked really hard to make sure that you get quality inbound links to your site… and you got them. A few years down the line you felt a need to change the look of your site. You did that, and possibly changes to some navigational structure. Knowingly or unknowingly you changed name or deleted a few pages. Whack – the inbound links to those pages are now showing a 404 error – i.e. page not found.

People coming to these pages get irritated or get confused and worst of all, the link juice you got from other websites vanished too! (Search engines don’t give any credit to inbound links that point to a non-existent page.) Heck due to this your rankings have also suffered.

Good News!

Now there is a way to find the sources linking to your sites’ not found pages. If you know the website that’s linking to your non-existent page, you can take some action like mail them and ask them to link to the right page or do something to make sure that visitors do not land into an ugly looking 404 page. What’s more you can even make sure that the search engines give your site the credit for inbound links.

Google webmaster blog recently announced that you can find the sources that link to your 404 error page.

You will need a Google Webmaster account and your site should be registered.

If you don’t have a Google Webmaster account, click here to register.

Those who have can login and then go to:
 
Diagnostics >> Web crawl

Under, “Errors for URLs in Sitemaps”, click on “Not found”.

Now you should see all the sources that have linked to your 404 pages.

The “Linked From” column contains the links of all sites linking to not found pages. You can download the data CSV file if you want.

Now that you know the source, you can mail them and request them to change the link to point to the correct page,

OR

You can do something so that your 404 page looks attractive and has all relevant links.

This way neither the visitors, nor the search engines will get angry.

The best way is to create a custom 404 page if your web-server supports it. Google can help you here.

There is a JavaScript code that Google generates for 404 pages. To get it login to your Google webmaster account then go to:

Dashboard > Tools > Enhance 404 pages

This should help you to generate the JavaScript code. Just copy and paste this into your custom 404 page code.

I am sure these tips will help you to improve your sites’ inbound link quality and help you to improve rankings too.

Recommended Reading:
 
1. Free Links To Your Site - Matt Cutts offering some more information on improving inbound link quality to 404 error pages.

2. Custom 404 pages - Google help page on Custom 404 pages.

3. Make your 404 pages more useful - More info on how to generate the JavaScript code to put in your custom 404 page.