Using the Link Checker
Drupal has a built-in Link Checker tool that can help alert you when links on your site are broken - whether they point to pages on your site, or are external.
To access the link checker report, click on Reports, and then Broken Links.
Reading the Broken Link Report
The URL column displays the URL of the link that is broken. You can click on this link to easily test if it appears broken to you, which can be useful since link checker occasionally generates false positives.
If you find a false positive, you can click Edit Link Settings under the Operations column to ignore that link in future scans.
Why Do I Get False Positives?
There are a variety of reasons. A common problem is when your link points to a page that requires users to login before they can proceed - since the link checker can't log into other sites, it will always getn an error when it tries to follow such links. Also, websites sometimes block tools like our link checker with their site's robots.txt file.
Response and Error Column
The Response column displays the HTML error code link checker found when it attempted to follow the link in the URL column. These codes can help you determine what exactly is wrong with the link.
What Do These Codes Mean?
There are a lot of possible error codes, but here are some of the most common ones you'll see in our link checker:
|404 -Not found||This link is completely broken.|
|301 - Moved permanently||
This means the page is now accessed through a different URL, and users who click this link are getting redirected to the new location.
These links are technically working, but you never know how long the redirect will stay up for. You should update these links to point directly to the new URL (which will load faster for your users anyway).
This usually happens when some type of authentication is required to access the page (link checker cannot authenticate).
You will see this error if you link to an unpublished page on a Drupal site.
The Operations column contains a link to the page that contains the broken link. This provides easy access if you have something like a 404 that you need to fix.
This column also contains a link to Edit Link Settings. The main reason you would use this is if you have false positives you want to prevent from showing up in your broken link report. You can uncheck the box next to Check Link Status to ignore false positives.