Slow SQL connection Windows 7

If you have a connection to Microsoft’s SQL, there are several things you can try-

First ~

Disable auto tuning level of the TCP. Please follow below steps:
1) Open command Prompt with admin right (Run as Admin)
2) Type “netsh interface tcp set global autotuninglevel=disabled”
3) After running above command restart the machine.

You can also try this next tip which seems to work best ~

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 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

Update –


Windows Vista and Windows Server “Longhorn” support Link-Local Multicast Name Resolution (LLMNR), which allows IPv6 hosts on a single subnet without a DNS server to resolve each other’s names. This capability is useful for single-subnet home networks and ad hoc wireless networks. Rather than unicasting a DNS query to a DNS server, LLMNR nodes send their DNS queries to a multicast address on which all the LLMNR-capable nodes of the subnet are listening. The owner of the queried name sends a unicast response. IPv4 nodes can also use LLMNR to perform local subnet name resolution without having to rely on NetBIOS over TCP/IP broadcasts.

Dawn M. Babian, GSAE

Disabling LLMNR (Below)

Professional or Enterprise (Gpedit.msc)

Home Edition

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.  (Except – Flow Control) Remember, not all adapters have advanced options – disable any settings that allow you to do so….

Disable your anti-virus and check the speed.  Is your anti-virus causing issues?

About TCAT Shelbyville IT Department

The Tennessee College of Applied Technology - is one of 46 institutions in the Tennessee Board of Regents System, the seventh largest system of higher education in the nation. This system comprises six universities, fourteen community colleges, and twenty-six Applied Technology Colleges.
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