Network

In this new blog post series I’ll be looking at (normally a selection of 3) cool articles, news and other blog posts that I find interesting during the day. For this week we have PowerShell tricks, a detailed article on securing the Windows Firewall and an (old but very interesting) write up on the woes of network administrators when everything goes wrong.

PowerShell tricks: Splatting
New to me (always learning!) this trick allows you to populate the parameters for a PowerShell cmdlet in a table (makes for much neater formatting) to then pass into the cmdlet as a single object.

Endpoint Isolation with the Windows Firewall
The Windows Firewall may seem like a bit of a beast from time to time but this article makes some great points on how to build out a set of secure policies that can apply to pretty much any environment.

All systems down
A true disaster story – quite old (2003) but really worth a read to see what lessons you can take home.

Have been having a bit of an interesting issue over the past few weeks whereby our Hyper-V Hosts (Dell T430 Tower Servers) would loose network connectivity at seemingly random intervals; the only resolution was to restart the server or to remove and replace the network cable.

After much investigation looking at the servers and associated network switch we discovered that only the Virtual Switches attached to the on board Broadcom NetXtreme adapters were having issues and that the Intel PCI card NICs were not.

That soon lead onto Microsoft KB 2986895 which relieved a known bug in the drivers for the Broadcom adapters that messed up the Virtual Machine Queues (VMQ) feature of Hyper-V causing a loss in network connectivity. The fix is either to update the driver to a version that does not have the issue or to disable VMQ.

More details can be found in this Microsoft KB… https://support.microsoft.com/en-us/kb/2986895