Category: LAN Networking

In Windows 7, all network devices yellow-flagged (code 31)
article #273, updated 2383 days ago

Saw this for the first time; on a Windows 7 laptop, all network devices except two, were yellow-flagged, and in their properties it said code 31, which means not able to load the driver files. In this condition, I found that I could not uninstall any network objects in Device Manager: it permitted me to do so, but immediately after the deletion was done, the objects remained.

I googled it a lot, found zero of real use, except the underlying pattern that apparently one very badly-behaved network driver or virtual device, can hose the whole Windows 7 networking stack in this very way.

In this case, there was a certain high-profile vendor’s VPN client installed, and it was this vendor’s items which were not yellow-flagged, but instead, were marked disabled. So I focussed on that, deleted the .sys file involved, and deleted every registry entry for them also, in safe mode, excepting only the LEGACY entries which I could not get permission to delete, even running regedit as administrator. No change: the objects remained after reboot.

I then tried System Restore, and took the OS back to the point before the issue began to occur. This had a very positive result; networking came back. The VPN client will need reinstalling, but I will update the machine all the way as next step, and then install the latest version of the VPN client.

Categories:   Network Hardware & Drivers   LAN Networking


A Unique Private IPv6 Subnet for Your LAN
article #263, updated 2399 days ago

IPv4 has the 192.168.*.*, 172.16-31.*, and 10.*.*.* ranges; IPv6 has one range that is enormously bigger than all of those three put together, which can contain 1,329,227,995,784,915,872,903,807,060,280,344,573 devices. The standard is to use a subnet randomly chosen, to minimize conflict when creating VPNs et cetera. The best tool I know for IPv6 subnet generation, is here:

You will need to tell Windows the size of your subnet. The default size is 64 on Windows, but this is quite enormous; a size of 16 is more than sufficient for a current LAN. Here is Windows configured for a IPv6 static with a 16-bit subnet, without v6 DNS as of yet:


Categories:   LAN Networking   Internet Networking


NAS reviews
article #194, updated 2587 days ago

A very good place to get info on NASes:

Categories:   Hardware   LAN Networking


Add IPv6 Reverse DNS to Server 2008
article #193, updated 2587 days ago

In Server 2008, the default protocol is IPv6.  It is not recommended to disable it in any way.

Default DNS, internal and LAN-wide, is therefore also IPv6.  All you really need is an AAAA record for the forward lookup.  But in many cases reverse lookup will have been skipped at server setup, and in such a case, it can get confusing to try to set up reverse DNS.  Reverse DNS is definitely recommended, it will smoothen out the LAN in general.

It has been very difficult to find any instructions to set up reverse IPv6 DNS on Server 2008.  Howsomever, here is one.

Categories:   DNS   LAN Networking


Windows 7 in an Older-Style Workgroup
article #161, updated 2665 days ago

If you have an older-style workgroup, XP and before, Windows 7 can cooperate.  Here are steps:

Provided by the excellent Rich McDaniel.

Categories:   LAN Networking   


JEB's NIC Checklist
article #143, updated 2727 days ago

JEB’s Network Interface Checklist
version 2.4, 2/3/2011

  1. Any changes to NIC configuration may cause the network interface to cease connecting for a little while.  If it’s a server, this counts as “server down” for at least a few minutes.  Occasionally, if a driver is old or the machine has not been rebooted in a long time, a reboot may be necessary for the NIC to work again after certain changes are made.  It is generally best to not make changes unless there are performance issues or specific concerns about network behavior — but without these changes, overall performance often goes down more than 50%.
  2. Install the most current drivers.  If the NIC is Intel or Broadcom, install the driver downloaded from Intel or Broadcom, not from Dell or other third-party packager.  Often a third-party packager will have separated the application (e.g., “Intel PROset Application”) from the driver (“Intel PROset Driver”); in such a case, the application needs to be removed before the update installation begins.  For Intel drivers, the fastest route for the download is to go to, search for “prowin32”, and click the link with the latest version (15.1.1 at this writing).  The link will take you to a page with both 32-bit and 64-bit drivers.
  3. For Server 2000, Server 2003, and XP, turn all offloading off.  This is actually a requirement, not just a recommendation, discussed in certain Microsoft reference materials.  In one case in the recent past, SBS simply failed to serve file or print to any workstation, unless this was done; in all cases thus far there has been an increase in general network reliability and performance when this is done.  On Intel NICs, this is often under “Performance Options”.
  4. For Server 2008, Server 2008R2, Vista, and Windows 7, turn all offloading on.
  5. For anything including “Scaling”, set it to “off” or “Disabled”, for 2000, XP, or Server 2003.  This is another Microsoft essential. There is a pack which is included in 2003SP2 which is said to make “Scaling” help, but it does not always help.
  6. For flow control, “Respond Only” (or “Rx Enabled”) is preferred, but if this is not available, set it to “On”.  This is not the same as “Rx Enabled” or “TX Enabled” under offloading!
  7. For Receive Descriptors and Transmit Descriptors on most NICs, set them to the maximum, unless the server is desperately low on RAM.  For some the maximums are 2048, for some one or the other is 5000, for others it is much less.  Each descriptor takes 2K of RAM.  Some Broadcom gigabit NICs will yellow-flag if they are set to 2048; for these, set receive to 750, transmit to 1500.
  8. For Adaptive Inter-frame Spacing, set it to “on” or “Enabled”.
  9. In the NIC’s “Power Management” tab, turn everything off.  This may have to be modified if Wake-On-LAN is used.
  10. In Server 2008, only one NIC (or one NIC team) is permitted to represent the server on the network. If there are two active NICs, you will have to turn one off, or crashes and unpredictable behavior will result sooner or later.
  11. In Server 2008, IPv6 must be turned on, and not deleted. It does not have to be configured, but it must be turned on.
  12. It is very much preferable, for Server 2008 and most especially for SBS 2008, for a working IPv6 subnet to be configured, even if the server(s) are the only devices which are able to use IPv6.

Categories:   Network Hardware & Drivers   LAN Networking


Out of memory/space issues, Server 2003/2008 and domain workstations
article #141, updated 2728 days ago

When workstations on a Server 2003 domain, report an insufficient memory and/or disk space profile error at login, try this:

It also appears to help general memory usage issues.  The same settings are listed by Microsoft in Server 2008 for an antivirus issue:

This one is from the indefatigable Liz Landry.

Categories:   Cleanup   LAN Networking


Windows was unable to find a certificate to log you on to the network (wireless)
article #134, updated 2756 days ago

How to fix this problem?  Try this:

Categories:   LAN Networking   Network Hardware & Drivers


Teaming NICs, Broadcom especially
article #130, updated 2780 days ago

If you have a Broadcom NIC listed for use with “Broadcom Advanced Control Suite 3”, you can team both Broadcom and Intel NICs.  Only catch:  you will need one static IP on your LAN for each.

Categories:   LAN Networking   Network Hardware & Drivers


Private IPv6 Address Range Generator
article #125, updated 2790 days ago

Here is an automatic generator of IPv6 private address ranges:

Categories:   Internet Networking   LAN Networking