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Windows 2012R2 DNS Server Subnet prioritization does not work with Wildcard RRs RRS feed

  • Question

  • We have the following setup configured:

    - internal test zone test.stackoverflow.com

    - Site A: 192.168.15.0/24; Site B: 192.168.20.0/24 (not our real ip space)

    - wild card RRs setup: *.test.stackoverflow.com -> 192.168.15.100 and *.test.stackoverflow.com -> 192.168.20.100

    Each site has a /24 in this example, and the mask bits are set correctly on the DNS server

    When we query nohost.test.stackoverflow.com the records are retured in random order, not in the correct subnet prioritized order.

    Prioritization works correctly for all other RR types except Wildcard RRs

    Friday, September 30, 2016 7:27 PM

Answers

All replies

  • Hi

    Configuring the resolver to perform subnet prioritization for records that it receives, you can configure the server to do the same for records that it sends. How the server behaves depends on the setting of the Enable round robin option on the Advanced tab of the server Properties dialog box in the DNS snap-in, and the value of the LocalNetPriority (REG_DWORD) registry entry in the following registry subkey as below:-

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\DNS\Parameters\

    You can also change the round robin setting from the registry, however, do so from the DNS snap-in instead.

    I think you need to re check your configuration to resolve the issue.

    regards.

    H. Shakir

    Friday, September 30, 2016 7:51 PM
  • I'm not sure I understand what you are saying. Why would this work correctly for all RRs besides the wildcard RR type?

    Friday, September 30, 2016 8:10 PM
  • Hi George Beech,

    I tested in my lab, both common RRs and wildcard RRs can do netmask ordering:

    Please check if you checked "Enable netmask ordering" in DNS properties, and do "ipconfig/flushdns" on the clients.

    Best Regards,

    Anne


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    Monday, October 3, 2016 4:13 AM
    Moderator
  • I just setup a new 2012R2 server and querying from a 2012 R2 server I get the same results.

    PS C:\Users\Administrator> nslookup a.test
    Server:  localhost
    Address:  127.0.0.1
    
    Name:    a.test
    Addresses:  196.168.15.7
              192.168.20.7
    
    PS C:\Users\Administrator> nslookup a.test
    Server:  localhost
    Address:  127.0.0.1
    
    Name:    a.test
    Addresses:  192.168.20.7
              196.168.15.7
    
    PS C:\Users\Administrator> nslookup a.test
    Server:  localhost
    Address:  127.0.0.1
    
    Name:    a.test
    Addresses:  196.168.15.7
              192.168.20.7
    
    PS C:\Users\Administrator> nslookup a.test
    Server:  localhost
    Address:  127.0.0.1
    
    Name:    a.test
    Addresses:  192.168.20.7
              196.168.15.7
    
    PS C:\Users\Administrator> nslookup a.test
    Server:  localhost
    Address:  127.0.0.1
    
    Name:    a.test
    Addresses:  196.168.15.7
              192.168.20.7
    
    PS C:\Users\Administrator>

    Above are my dns settings

    Monday, October 3, 2016 6:28 PM
  • Hi Geroge Beech,

    I noticed your DNS server is 127.0.0.1, do you test in your DNS server?

    Please test in your DNS clients. In my test, query on DNS server itself, it also doesn't use netmask ordering, while DNS client could.

    Best Regards,

    Anne


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    Thursday, October 6, 2016 4:31 AM
    Moderator
  • Here is the nslookup from a 'client' Windows 2012R2 servers. Same result against the WC RR

    Thursday, October 6, 2016 9:55 PM
  • Hi George Beech,

    Apologize for my incorrect test above.

    Since I'm not familiar with WC RR, my test above is not correct. Here is the right things (I learn it from your screenshot). And, yes, seems WC RR don't do Subnet prioritization:

    Best Regards,

    Anne



    Tuesday, October 11, 2016 8:49 AM
    Moderator
  • Hi George Beech,

    Could the above replies be of help? If yes, you may mark it as answer, if not, feel free to feed back.

    Best Regards,

    Anne


    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, October 24, 2016 1:31 AM
    Moderator