Enterprise computing is tough – Here’s some tips

Here’s a few tips we use when optimizing and troubleshooting computers and mobile devices on our network.   Remember Windows 8 is a different operating system and Windows Surface tablets can be a true productivity tool.

Jumbo Frames – What are they?  How can they help in the Enterprise?

In a gigabit network, you should enable jumbo frames and tweak the jumbo frame settings on your nic so that large files can transfer at greater speeds.  In a packet of data, the header will remain the same but the payload size will increase.  You should do this if you have gigabit switches and gigabit cards in place.  Normally network cards will allow for tweaks of the Jumbo frame by several MTUs.   With gigabit switches in place, the receiving switches may be 10/100 and the computer on the other end will not see a great benefit from this.  However if you have cards in computers that are connected to a switch (1000 mbps/1 Gbps)  and a NAS that supports Jumbo frames, the data transfer from these computers (normally a Server) will benefit from this tweak.

Ideally you would want your entire network on gigabit.   In today’s economy,  many if not most networks are a  hybrid (a mixture of 1000 or 100 mbps) nodes (printers, computers, switches).  There’s only one way to find out about performance.  Transfer a large file (ISO or several megabytes) and time it slowly tweaking the MTU settings under the network card’s property.

Slow SQL Connection
If you have a connection to Microsoft’s SQL, there are several things you can try if response times seem slow-

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 224.0.0.252 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 –

LLMNR

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, GIAC
Instructor

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

Odd Network connectivity or no connectivity

  • Click Start Menu, type cmd in the search box or run box ( Hold down Ctrl + Shift and hit Enter)Type the following commands, each followed by pressing enter.
  • ipconfig /flushdns
  • nbtstat -R
  • nbtstat -RR
  • netsh int reset all
  • netsh int ipv4 reset
  • netsh winsock reset catalog
This will rebuild the tcp/ip protocol stack (fully)

After rebooting, run a command prompt as an administrator and type:

  • netsh interface tcp set global autotuninglevel=disabled

Reboot

See also –
Speed up Windows 7 and Vista internet connections

Red X on Network icon
Have you ever experienced a red X   on the network icon in the taskbar on Windows 7?

Symptoms –

  • Red X on the network icon (by time on taskbar)
  • Still able to go to the internet

Click “Start or orb”
Run or Search box
type “dcomcnfg” and hit enter
Find: Component Services-Computers-My Computer-DCOM Config-netprofm
Right click “netprofm”
Click on “Properties”  select “Security”
Navigate to “Launch and Activation Permissions” section changed to “Customize”
Click “Edit”
Click “Add..”   Type “LOCAL SERVICE” as the object names then click “OK”
In “Permissions for LOCAL SERVICE”, select “Allow” for “Local Launch” and “Local Activition”  Click  “OK”, Click “OK”
Reboot

All of the Windows Services should restart and you should be able to join domains, have the icon repaired and be able to perform all network tasks.

Other common problems may be-missing Network Adapters under connections

If you have this problem (above) you may need to re-register 3 dlls. Follow these steps. (Error normally found in Windows XP or 7)

Start, Run. cmd.exe

regsvr32 netshell.dll
regsvr32 netcfgx.dll
regsvr32 netman.dll

Also make sure Simple TCP/IP is enabled by following these steps:

a. In Control Panel, double-click Add or Remove Programs.
b. Click Add/Remove Windows Components.
c. Click Networking Services, and then click Details. Verify that Simple TCP/IP Services is turned on

Slow Network Response
If you have slow or non responsive program properties; such as a database or other network program…Right Click on My Computer, go to Properties, select Hardware, Device Manager, click the + sign on Network, Right Click on your network card, select properties, select the Advanced Tab, Look for Speed   – adjust the value to 100 Full Duplex, 100 Half or even select the 10 settings.  Try it on each of the settings to see which one is optimal for your network.

When computers handshake (exchange data) autosense does not always work.

I’ve had replaced network cards, ran winsock fix and tried everything when the solution was right in front of me.  Don’t let vendors tell you that you need a new computer.

Device connectivity problems with NAS or SANS

You may have devices on your network that you can no longer connect (Vista/Windows 7) to or you may not be able to network to Windows XP (for whatever reason, this works).  Actually this changes settings to accept NTLMv1 and NTLMv2 so that you can connect to Samba Servers, Snap Servers, Older Windows Computers or whatever….

1. Go to Run, Type Regedit and open this key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa

2. If it doesn’t exist, create a DWORD value named
LmCompatibilityLevel

3. Set the value to 1

4. Reboot

Optimizing your computer – Another Opinion
We are often asked how we optimize a netbook, laptop or desktop by many students.   If you have completed some of these steps, simply skip them and go to the next item.  Here’s our tip sheet –

____  Right click on desktop, enable all desktop icons

____  Right click Computer or in home navigate to users under the control panel, enable the administrator account

____  Set administrator password

____  Change Workgroup to whatever you want

____  Go to Device Manager, double click wireless card and LAN card, click advanced tab, disable all services except radio. Click on power management tab, uncheck “Allow computer to turn off this device to save power.  Go to the network and sharing center, click on change adapter settings, hit the ALT key, go to Advanced, go to Advanced Settings, highlight the wireless or LAN network connection and move the one you use the most up.

In the Network and Sharing Center, Go to Change Advanced Sharing Settings, Turn off Media Streaming if you won’t be streaming video or music.

In the Network and Sharing Center, change adapter settings, under the wireless card and LAN card settings, double click TCP/IP 4, click advanced, Click WINS and enable NetBIOS over TCP/IP

____  Go to command prompt as an administrator and enter the following commands to optimize your network:

netsh int tcp set heuristics disabled
netsh int tcp set global rss=disabled
netsh int tcp set global chimney=disabled
netsh int tcp set global autotuninglevel=normal
netsh int tcp set global congestionprovider=ctcp
netsh int tcp set global ecncapability=disabled
netsh int tcp set global timestamps=disabled

Modify LLMNR by doing the following:

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

IPv6 Optimization

Instead of trying to impress everyone with bits, bytes and binary, we’re trying to put these tips in layman terms for young IT professionals (quick start guides).

If you have installed your Teredo drivers and IPv6, you should receive a 2001: IP address on your Tunnel adapter if you do an ipconfig at a command prompt.   You can assign your self an ipv6 address based on this scheme if you are behind a router (home wireless or other) That is not IPv6 compliant.  How?

Teredo is a protocol that works behind NATed devices – (by the way, NAT is going away…yes going away.  Stateful firewalls and the security of IPv6 won’t require NAT anymore after you are 100% compliant)

It breaks down like this.  Your router gives you an IPv4 address with its DHCP server.  The IPv6 address you want is an  IP address a 128 bit address instead of 32 bits.   To see newer IPv6 websites, you’ll need Teredo to get you there (both IPv4 and IPv6).   So how does an IPv6 address break down?

Prefix     –    Teredo Server IPv4     –    Flags      –    UDP Port        –   Your IP address(Teredo Client)
2001:0:           4136:e378:                       63bf:              8000:                     c0a8:0405   <- is 192.168.4.135 (Example)

So the first part doesn’t change (Prefix/Teredo Server/Flags/UDP Port) but where do you get the Teredo Client address?

You can take your ip address (IPv4) and put it into a conversion utility and  after the conversion, you but the hex number  to where the Teredo Client goes (above).

Is it working after you put it (The ip address)  into your network adapter statically?

Note:You won’t need a gateway or DNS in the IPv6 section – however you will need an IPv6 DNS server address that has an IPv4 numbering scheme to put in your router?

Global Eye Candy Chart

Arin’s wiki page on IPv6 Troubleshooting

Feel free to use Twitter, Facebook or the links below if this has helped you!   Please leave comments and suggestions that will help home users or businesses.

Creating a Roaming Profile

Don’t forget, the fastest hard drive without IPv6 ….check your network info here

Attached are guides on creating a roaming profile with Windows 7 and Server 2008 r2.

(Thanks to Mr. Ledlow for creating these)

Guides are in PDF
Step One Create a User on the Domain

Step Two Creating a Folder on the Domain

Step Three Creating the Profile

Step Four Join the Domain

A roaming profile allows the domain user to login and keep their preferences regardless of where they login.

See our review of Windows 8 and see how you can run 90% of your programs, virtualize other operating systems, use your network and more.

Also go and Tweak your wireless!!

RichardKok  Reset a Roaming Profile

Other info

http://www.grouppolicy.biz/2010/08/best-practice-roaming-profiles-and-folder-redirection-a-k-a-user-virtualization/

http://blogs.technet.com/b/askds/archive/2008/06/17/user-profile-policies-in-windows-server-2008-and-windows-vista.aspx

http://blogs.technet.com/b/askds/archive/2008/06/30/automatic-creation-of-user-folders-for-home-roaming-profile-and-redirected-folders.aspx

http://support.microsoft.com/kb/555046

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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