Troubleshooting high autodiscover.xml usage


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  • Applies to: Grid
    • Difficulty: Easy
    • Time Needed: 10
    • Tools Required: AccountCenter access
  • Applies to: DV
    • Difficulty: Easy
    • Time Needed: 10
    • Tools Required: Administrator access

Overview

The following article provides information on how to troubleshoot high server usage from autodiscover.xml. This file is associated with the use of mail software. The issue can occur when the mail software in question incorrectly and repeatedly calls for an "autodiscover.xml" file.

If left unmanaged, this may eventually start using unnecessary resources and load on your server. This can potentially result in a slower site or resource overages.

Stopping the repeated requests at the source may require speaking to your website's developer or contacting the support team of the associated mail software. However, there are some provisional solutions that can be employed to help mitigate the resource usage that autodiscover.xml can cause.

STATEMENT OF SUPPORT:
Please keep in mind that troubleshooting the configuration/functionality of third-party applications is not covered by our statement of support. These resources were provided as a courtesy to assist you to the extent of our abilities. For more information on our statement of support, feel free to click here.

 Diagnosis  

One of the telling signs of an autodiscover.xml issue is finding multiple requests for that file in your logs. logs. These may be returning as 404 errors. This is because autodiscover.xml often doesn't actually exist on your site, and is simply being called for in error.

For legacy Grid users, a helpful resource is the GPU tool. This will allow you to see exactly how much of an issue autodiscover.xml is causing to your server.

GPU-2.png

Instructions

.htaccess

One option is to block/redirect these requests through the .htaccess file:

  1. First, we will want to create the file path that is being called for. This will typically be example.com/autodiscover/autodiscover.xml. You can check your logs to confirm the file path.

    (replace example.com with your ACTUAL domain name).

  2. SSH, FTP, or a File Manager can be used to create the file path. In this example, we will be using FTP. FTP.
  3. Connect to your site through FTP. Ensure you are in your site's root directory. root directory.
  4. Create a new directory and name it autodiscover.

    FTP-1.png

  5. Navigate inside of the newly created autodiscover directory.
  6. Create a file named autodiscover.xml

    FTP-3_png.png

  7. Return to your site's root directory and edit the .htaccess file.

    FTP-4_png.png

  8. Insert the following code to your .htaccess file:
    Redirect 204 /autodiscover/autodiscover.xml
    FTP-6.png
  9. Save your changes.
  10. Now try to navigate to example.com/autodiscover/autodiscover.xml using a web browser. The URL should not load any content. This should indicate that the URL is returning a 204 No Content response which is cachable by default. This should help mitigate resource usage.

(mt) Security 

Another option is to utilize a Web Application Firewall (WAF) that has URL blocking capability. Our (mt) Security service comes with a WAF included. If you'd like more information on this service, feel free to click here.

NOTE:
The (mt) Security WAF requires that your domain's nameservers be pointed to (mt) Media Temple. If you wish to know more information about nameservers, feel free to review the articles below:

  1. Log into your Media Temple account center.
  2. Locate the Security & CDN menu and click on SECURITY DASHBOARD.

    WAF-1.png
  3. If your site hasn't been added to (mt) Security yet, click on Add Site.

    WAF-2.png

  4. Type your site name (omitting "http" or "www") and click Add Sites.

    WAF-3.png
  5. Once your site has been added, click on the box associated to your domain.

    WAF-4.png

  6. Click on FIREWALL. If necessary, activate the firewall. (this may take a few minutes to complete).

    WAF-5.png

  7. Click on Access Control. Then click on Blacklist URL Paths.

    WAF-6.png

  8. Type /autodiscover/autodiscover.xml in the data section. Then click Blacklist.

    WAF-7.png

  9. You should now see /autodiscover/autodiscover.xml in the list of blocked URLs.

    WAF-8.png

  10. Due to caching, you may need to wait some time to view the effects of the WAF. However, eventually when attempting to visit the /autodiscover/autodiscover.xml URL through a web browser, you should see a firewall block. This method should also mitigate resource usage.

    WAF-9.png