• Our team is looking to connect with folks who use email services provided by Plesk, or a premium service. If you'd like to be part of the discovery process and share your experiences, we invite you to complete this short screening survey. If your responses match the persona we are looking for, you'll receive a link to schedule a call at your convenience. We look forward to hearing from you!
  • The BIND DNS server has already been deprecated and removed from Plesk for Windows.
    If a Plesk for Windows server is still using BIND, the upgrade to Plesk Obsidian 18.0.70 will be unavailable until the administrator switches the DNS server to Microsoft DNS. We strongly recommend transitioning to Microsoft DNS within the next 6 weeks, before the Plesk 18.0.70 release.
  • The Horde component is removed from Plesk Installer. We recommend switching to another webmail software supported in Plesk.

Gracefully Handling Microsoft AutoDiscover Inquiries

Rachel Moorehead

New Pleskian
Greetings!

Environment:
RHEL 6.6
Plesk 12.0.18 RedHat el6 1200151014.14

Background: We've recently switched to a Microsoft Exchange based email service. As a part of the email client configurations, Microsoft uses a utility called AutoDiscover. AutoDiscover has a predefined set of URLs that it attempts to connect to in order to find its Exchange server. Unfortunately the first URL it tries is https://emaildomain.com/autodiscover/autodiscover.xml. Which for most people "emaildomain.com" is also their primary website domain so this traffic gets served to the web server first, which provides a 500 response and AutoDiscover moves on to its next predefined URL to try.

For a hosting provider with hundreds of web domains that are also email domains, this is slowly becoming a load and log growth problem as AutoDiscover attempts to connect every time an email client is open and hits the server at least 5 times in one pass.

Question: Is there a quick, easy way to say for any https://*/autodiscover/autodiscover.xml that gets served to Plesk to deny with little server-side overhead?

Here is a log snippet for example:

<ip address> - - [30/Dec/2015:10:54:07 -0500] "POST /autodiscover/autodiscover.xml HTTP/1.1" 500 17666 "-" "Microsoft Office/16.0 (Windows NT 10.0; Microsoft Outlook 16.0.4266; Pro)"
<ip address> - - [30/Dec/2015:10:54:45 -0500] "POST /autodiscover/autodiscover.xml HTTP/1.1" 500 16000 "-" "Microsoft Office/16.0 (Windows NT 10.0; Microsoft Outlook 16.0.4266; Pro)"
<ip address> - - [30/Dec/2015:10:59:26 -0500] "POST /autodiscover/autodiscover.xml HTTP/1.1" 500 16000 "-" "Microsoft Office/16.0 (Windows NT 10.0; Microsoft Outlook 16.0.4266; Pro)"
<ip address> - - [30/Dec/2015:11:01:06 -0500] "POST /autodiscover/autodiscover.xml HTTP/1.1" 500 17666 "-" "Microsoft Office/16.0 (Windows NT 10.0; Microsoft Outlook 16.0.4266; Pro)"
<ip address>- - [30/Dec/2015:11:04:36 -0500] "POST /autodiscover/autodiscover.xml HTTP/1.1" 500 17666 "-" "Microsoft Office/16.0 (Windows NT 10.0; Microsoft Outlook 16.0.4266; Pro)"
 
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