Exchange 2010 with NLB on HP ProCurve

Assuming you plan to implement Microsoft Exchange 2010 and have some budget left, what do you do?
We decided to support the project with an external Exchange-specialized consultant. So far so good.

After going through the design-phase we worked out the following Exchange installation plan:
- 2 mailbox stores, with database availability group (DAG)
- 2 combined clientaccess (CAS) and hub/transport (HT) servers, with network load balancing (NLB)

The installation went more or less quick and smoothly. But afterwards..

I'm picking out one (hopefully interesting) issue, we sorted out a few days later.

During an internal network scan, we were surprised about the following finding:
The broadcast got an intermittent strong increase.

Futher analyzing showed up: multicast traffic from NLB was flooding all ports within the same vlan, instead only the designated ports.

How can this happen?
Cause #1: The Exchange-specialist knows how to click through the NLB setup, but had no in-depth knowledge of it.
Cause #2: The network switch, on which Exchange NLB was attached to, was an HP ProCurve.

Solution: A static MAC entry needs to be configured on the switch.

So we thought this could be fixed quite easy, but were brought down to earth very quickly..
After trying to set the required static entry, the following error appeared:

 PROCURVE(config)# static 03bf0a-c8027e interface A2
 Value static is invalid.

It turned out, that the used HP ProCurve switches were not accepting Microsoft NLB MAC addresses...


How to succeed?
Buy other switches, VLAN it off or check the NLB multicast IGMP option.



There is a sample configuration for Cisco switches available at vmware.com:
http://kb.vmware.com/kb/1006525

Slow RDC / SQL performance using Windows 7 / 2008 R2

Are you experiencing slow remote desktop connections (RDC)?
Or is the database-connect to your SQL server not working properly?

Then have a look at the following Windows feature: Receive Window Auto-Tuning
http://support.microsoft.com/kb/934430/en-us

Right-click Command Prompt, and then click Run as Administrator.
To display the current setting, type the following command, and then press ENTER:

 netsh interface tcp show global

You will find the "Receive Window Auto-Tuning" set to normal.

To disable this feature, type the following command, and then press ENTER:

 netsh interface tcp set global autotuninglevel=disabled


Generally, it seems to be a good idea to disable this feature in a business-related environment.
I've seen this autotuning feature too often screwing up network traffic..



For more information, visit the following site:
http://technet.microsoft.com/en-us/magazine/cc162519.aspx

dot1q - Configuration on Cisco/HP switches

Have you ever mixed up Cisco and HP switches in a networking environment?
It's funny how similar features can be named differently - and vice versa (e.g. meaning of 'trunk').

Now, assuming you're planning to connect HP switches (4200 series) to Cisco switches (3500 series). The first steps for configuring such a 'trunk' on Cisco switches were:

interface GigabitEthernet0/1
 switchport trunk encapsulation dot1q
 switchport mode trunk
exit 
interface GigabitEthernet0/2
 switchport trunk encapsulation dot1q
 switchport mode trunk
 switchport nonegotiate
exit

It's recommended to disable Cisco's DTP signaling (using the nonegotiate option) when connecting to HP ProCurve switches.

By default, all VLANs were allowed to pass the Cisco trunk.
To manually specifiy the allowed VLANs (e.g. 1, 10 & 11), add the following command:
 switchport trunk allowed vlan 1,10,11

On HP switches, ensure that the "Native VLAN" (usually VLAN1) is set as untagged on the uplink port (A2):
 vlan 1
 untagged A2
 exit

Checking the port status on Cisco:

show interface GigabitEthernet0/1 switchport


For more information, visit the following sites:

"Trunking" on Cisco switches
http://www.ciscopress.com/articles/article.asp?p=29803&seqNum=3

ProCurve / Cisco Interoperability Guide
http://www.tecnocael.it/ftp/docs/ProCurve_Cisco.pdf