Windows using the DNS suffix search list on all lookups, even valid FQDNs. How to stop this

dnswindows xp

When doing DNS lookups (specifically using nslookup, for some reason most things are not effected) Windows XP Pro SP3 is using the DNS suffix search list for every single one. Even for fully qualified domain names. For example I lookup "www.microsoft.com" but windows actually asks for "www.microsoft.com.eondream.com" (eondream.com is my primary domain). Now I can fix the issue by removing the Primary DNS suffix, but it seems to me that the DNS suffix search list should be for short, invalid names (where dots=0 or something). I'm sure I have a misconfiguration somewhere in windows but I don't know where. I've changed every option I can think of or find.

Below is the output of ipconfig /all and nslookup (with debug & db2 enabled). This is using a static IP & (internal) DNS server.

C:\>ipconfig /all

Windows IP Configuration

        Host Name . . . . . . . . . . . . : frayedlogic
        Primary Dns Suffix  . . . . . . . : eondream.com
        Node Type . . . . . . . . . . . . : Unknown
        IP Routing Enabled. . . . . . . . : No
        WINS Proxy Enabled. . . . . . . . : No
        DNS Suffix Search List. . . . . . : eondream.com

Ethernet adapter Wireless Network Connection:

        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : Dell Wireless 1390 WLAN Mini-Card
        Physical Address. . . . . . . . . : 00-1B-FC-29-EB-6B
        Dhcp Enabled. . . . . . . . . . . : No
        IP Address. . . . . . . . . . . . : 192.168.13.32
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.168.13.13
        DNS Servers . . . . . . . . . . . : 192.168.19.19

C:\>nslookup
Default Server:  shardik.eondream.com
Address:  192.168.19.19

> set debug
> set db2
> www.microsoft.com
Server:  shardik.eondream.com
Address:  192.168.19.19

------------
Got answer:
    HEADER:
        opcode = QUERY, id = 2, rcode = NOERROR
        header flags:  response, want recursion, recursion avail.
        questions = 1,  answers = 1,  authority records = 0,  additional = 0

    QUESTIONS:
        www.microsoft.com.eondream.com, type = A, class = IN
    ANSWERS:
    ->  www.microsoft.com.eondream.com
        internet address = 208.69.36.132
        ttl = 0 (0 secs)

------------
Non-authoritative answer:
Name:    www.microsoft.com.eondream.com
Address:  208.69.36.132

(Note: it resolves to that IP because I use the opendns service and that is their suggestion page or whatever you want to call it)
If I am reading the nslookup output correctly then it is not a problem with my DNS server because windows is actually asking for the incorrect domain.

Best Answer

Well, I'm no expert, but here's what I found:

This registry entry works for both Windows XP and Windows Vista

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\DNSClient]
"AppendToMultiLabelName"=dword:00000000

HKLM\Software\Policies\Microsoft\Windows NT\DNSClient\AppendToMultiLabelName
Type = DWORD

Data:

  • 0 (Do not Append Suffix)
  • 1 (Append suffix)

If the registry entry is not present, the default in Windows XP is 1, and 0 in Windows Vista.

Note: This registry changes and its effect apply only to the ping command, they do not apply to the nslookup tool. This is because nslookup contains its own DNS resolver and does not rely on the resolver built into the operating system (DNS Client). The DNS (multi-label) query packets sent by the nslookup tool will append the domains listed in the suffix search order irrespective of the registry key settings mentioned here.

Reference: http://blogs.technet.com/networking/archive/2009/04/16/dns-client-name-resolution-behavior-in-windows-vista-vs-windows-xp.aspx

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