Windows DNS Domain Suffix Search List Entry Limitation of 50 entries

Hi All,

another blog entry from the MS Romanian Networking Team.

Consider the following scenario:

- one or more applications which need to make name resolution by using host name (single-tag)
- the DNS client will be using the DNS suffix search list configured on the DNS client machine
- a lot of DNS zones, and I mean a lot…

Everything runs smoothly, until the number of DNS zones has reached 51.
Then you notice that the 51st DNS zone can be added to the DNS suffix search list, but it will not be considered when performing name resolution. And there is a very good explanation for this behavior:

By design, the DNS Suffix Search list in Windows is limited to 50 entries.

Although there is no limitation to the number of entries that you can add from the user interface on the Advanced TCP/IP Settings DNS tab, the DNS resolver uses only the first 50 entries to build the DNS suffixes. This hardcoded 50 entries limit cannot be influenced by Administrators.

This limit applies to all Windows operating systems up to and including Windows Server 2012 R2 and Windows 10.

Please NOTE:
This behavior was validated through code review as we write this article - August 5th, 2016 – but could change in future Windows operating system releases or with any future Updates for Windows operating systems already released.


For additional information about domain suffixes, click the article numbers below to view the articles in the Microsoft Knowledge Base:

275553 How to Configure a Domain Suffix Search List on the DNS Clients

178277 INFO: Setting DNS Domain Suffix Search Order During an Unattended Installation