Setting The MTU In Windows Vista

Long ago, when I first heard of the dynamic tuning in the Windows Vista TCP/IP stack, I envisioned the manual setting of the static MTU to be a thing of the past. Unfortunately, I was wrong - the MTU is still a fixed setting, in Vista.

The legendary tool, DrTCP, which is used by everybody to change the MTU in Windows 2000 and XP, doesn't work under Windows Vista. Fortunately, Microsoft now allows us to adjust the MTU using the "netsh" command. As other commands in Windows Vista, you run "netsh" using the command window, in Administrative mode.

To see what interfaces you have on your computer, type

netsh interface ipv4 show subinterfaces

To change the MTU, type

netsh interface ipv4 set subinterface "Local Area Connection" mtu=nnnn store=persistent

where

Local Area Connection is the name of the network connection on your computer, from the list obtained above.
nnnn is the desired value for MTU.

Reboot after making the change.

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Windows Vista And The IPX/SPX Protocol

Along with providing IPV6 as a default network protocol in Windows Vista, Microsoft made another major change to the protocol stack there - they eliminated the optional IPX/SPX selection. Microsoft now does not support IPX/SPX, in any way.

Note:
Windows Vista does not provide a NetWare client or the IPX/SPX protocol.

You can get a Novell client, from Novell. We haven't confirmed that this is IPX/SPX, though.

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Windows Vista Is Maturing

Windows Vista is maturing, and based upon various complaints about different issues, Microsoft has started issuing comprehensive updates.

In September, Microsoft issued (KB938979): An update is available that improves the performance and reliability of Windows Vista. Last week, Microsoft updated that update, with (KB941649): An update is available that improves the compatibility, reliability, and stability of Windows Vista.

Among the issues hoped to be mitigated by this update are the Vista Printing problems of various symptoms. We'll be watching the effects of this update, closely.

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The Run Window

Many times, when I ask somebody to diagnose their problem, I'll ask for useful material like an "ipconfig" log. I'll ask that they

Open a Command window, and type "ipconfig /all".

and they respond with

I did. A window opened, and closed, and I couldn't read a thing.

What was just described was not the Command window, it was the Run window.


The Run window works great, for Windows applets. Use the Command window for Command applications. Simply type "cmd" here, and hit the Enter key, or the OK button, when you are producing a diagnostic log that I request.




And a Command window should open for you.



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Changes In Internet Explorer Security May Affect Local Network Access

Many owners of third party firewalls such as Norton Internet Security and Zone Alarm, which filter access between computers by zones, are used to the idea that personal firewall settings can affect the ability of various computers on their local network to be accessed from other computers.

Recent changes to Internet Explorer may also have an effect on how your computers, on your local network, are accessed from each other. If you use My Network Places (aka Network in Windows Vista), you may be accustomed to seeing all computers on your local network listed with a Network Location of "Local Network".

Some owners of computers running Microsoft Windows are reporting that local shares now list with a Network Location of "Internet".

It appears that this oddity can be controlled through the (Internet Options - Security - ) Local Intranet - Sites wizard in Control Panel.


This is the default setting, causing local computers to be listed as "Internet".



This is the currently effective setting, causing local computers to be listed as "Local Network".



This behaviour appears to be independent of the status of Windows Firewall. It's quite likely that this will affect more than just the display of the various computers in My Network Places.

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