Finally found a small problem with Windows 7. After upgrading, we have discovered that Windows 7 was responding slow to our SQL Server 2005. What we discovered is below.
Slow response times in Windows 7 to a SQL Server can be due to the LLMNR protocol. This may be resolved by turning off the LLMNR protocol.
LLMNR is a protocol that allows both IPv6/4 computers to perform name resolution for the NetBIOS names of other computers without requiring a DNS server.
IPv4 hosts can use NetBIOS over TCP/IP (NetBT) to resolve computer names to IPv4 addresses for neighboring computers by broadcasting a NetBIOS Query.
All IPv4-based LLMNR hosts listen on the IPv4 multicast address 126.96.36.199 instruct their Ethernet network adapters to listen for Ethernet frames with a destination multicast address.
Windows Vista and 7-based LLMNR computers do not send or respond to unicast queries.
To disable LLMNR:
Modify Group Policy – Go to Search – Type GPEdit.msc – Enter – Navigate to the following and make sure Enabled is checked -
Computer Configuration\Administrative Templates\Network\DNS Client
\Turn off Multicast Name Resolution = Enabled
How does Multicasting Work? Here’s a good explanation
Dawn M. Babian, GSAE
Disabling LLMNR (Below)
Professional or Enterprise (Gpedit.msc)
Create a registry key as follows -
You also should go to your network adapter properties and disable all of the settings under the advanced properties such as TCP/Offload and other advanced settings. Remember, not all adapters have advanced options – disable any settings that allow you to do so….
See our article -