SSL Certs And Achieving “A” Level Security With Older Windows Versions


So a mate of mine pings me. Says they have an problem with their web mail SSL security  (Exchange 2010) running virtualized on Hyper-V.  The security guy states they need to move to a more secure platform that supports “modern SSL standards” and proposes to migrate from Exchange 2010 to Exchange 2013 in an emergency upgrade. Preferably to VMware as “MickeySoft” is insecure. Oh boy! Another profit of disaster who says the ship is lost unless …

You immediately know that the “security guy” is an incompetent fraud who only reads the IT press tabloids, runs some  freely available vulnerability toys (some are quite good) to determine what to check off on his list and shout out some “the sky is falling” rubbish to justify his daily rate and guarantee his paycheck. I’ve said it before, your mother told you not to trust strangers just like that, so why do so many companies do this with “consultants”? Choose your advisers wisely and remember Machiavelli’s notes on the use of mercenaries Winking smile!

  • VMware is not more secure than Hyper-V. That’s so wrong and so loaded with prejudice it immediately invalidates the persons credibility & reputation. If you need proof, do your research but as a recent example the “HeartBleed” issue left VMware scrambling, not Hyper-V. And for what it’s worth. IT security is like crime, statistically we’ll all be victims a couple of times in our life time.
  • Exchange 2010 running on Windows 2008R2 fully patched is just fine. So what was all the drama about? The issue was that the Qualys SSL Labs tool gave their Outlook Web Access a F grade. Why? Well they still allowed SSL 2.0, they didn’t run TLS 1.2 and they don’t have Forward Secrecy support.

My advice to my buddy? First he needs to get better security advice. Secondly, to get an “A” for secure SSL configuration all you need to is some easy tweaking. You don’t want to support any clients that can’t handle the better SSL configurations anyway. No one should be allowed to use these anyway. But what do I use? SSL 3.0? TLS 1.0/1.1/1.2? What to use & do? Here’s some documentation on how to enable/disable protocols: How to restrict the use of certain cryptographic algorithms and protocols in Schannel.dll. This will tell you how to do it? But which SSL versions can you dump today without suffering to many support calls. Server side, drop SSL 2.0 & SSL 3.0, keep TLS 1.0/1.1/1.2. On the client side you’ll need to do the same. That will keep most things working. Not ideal but the trick is to allow / enable the better protocols server side so all clients that can use it, can use it, while you block the really bad ones that just don’t have any use any more. We’ll play a bit with this.

Test 1: Disable SSL 2.0 and Enable SSL 3.0

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As you can see this gave them an B grade. We need to enforce the current best TLS 1.2 protocol to get that and we might want to get rid of SSL 3.0 as XP &n IE 6.0 have had there time and that’s over.

Test 2: Enable TLS 1.2

There you go. I hope this helps you out if you need to make sure you environment supports only more modern, stronger protocols.

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There it is. A- Smile Compliance achieved! Now it would best to disable SSL 2.0/3.0, TLS 1.0/1.1 on the server and forget about any browsers, operating systems and software that can’t handle it. But that’s not that easily done you’ll need Outlook 2013 for RPC over HTTP if you want to enforce TLS 1.2. But as far as the auditors go they are all so happy now and effectively you’re now supporting the more modern clients. Now my buddy can get to an A or A+ rating when they make sure to get Forward secrecy support in the future. I really advise the latter as HeartBleed made it obvious the wide use of this is long overdue.

Some Testing Fun

Grab a laptop, WireShark and a number of twitter clients, cloud storage products and take a peak a what version of SSL/TLS those apps use. Some tests you can do:

MetroTwit uses SSLv3, OneDrive uses TLSv1, Yammer seems to be at TLSv1 as well. Try disabling TSL 1.0 on a client and see how it breaks Outlook  2010 RPC over HTTPS and even OneDrive by the way.

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What you can get away with depends on the roles of the servers and the level security the clients for that role can handle.

Won’t this break functionality?

As you’ve seen above it can but for what matters on the e-mail server, probably not. If it does you’re in need of some major work on your client infrastructure. But in most cases you’ll be fine, especially with web browsers. But I have a underpaid employee who needs food stamp support so she cannot afford to upgrade her PC from Windows XP! Dude, pay a decent living wage, please. That aside, yes you can turn on better protocol support and block the oldest, most insecure ones on your servers. You call the shots on the use of your businesses infrastructure and you are under no obligation to allow your employees to access your services with obsolete clients. You want to be in the green zone, in the right column with TLS 1.2 if possible, but that’s going to be a challenge for a lot of services.

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Do as I say, don’t do as I do

The funny thing is that I ran the same test against the web (mainly e-mail) servers of 4 governments levels that are enforcing/promoting the (mandatory) use of security officers in an attempt to get to a more secure web for the benefit of all man kind. Not only does this fail because of such fine examples of security officers but 2/3 don’t seem to take their own medicine. The intentions are good I’m sure but the road to hell is paved with those and while compliancy is not the same a being secure, even this is hard to get to it seems.

Federal Government Department

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Undisclosed State Government

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Undisclosed Local Government

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Medium Sized City (they did well compared to the above braches with more resources)

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Don’t panic

That’s what it says on the cover of “The Official Hitchhiker’s Guide to the Galaxy Companion”. Get some good advise and if you want or read more about how the rating is done (as of 2014) then please read this SSL Labs: Stricter Security Requirements for 2014 which also provide a link to their SSL Server Rating Guide.

DELL Enterprise Forum EMEA 2014 in Frankfurt


As you might have noticed on Twitter I was in Frankfurt last week to attend DELL Enterprise Forum EMEA 2014. It was a great conference and very worthwhile going to. It was a week of multi way communication between vendor, marketing, engineering, partners and customers. I learned a lot. And I gave a lot of feedback. As a Dell TechCenter Rockstar and a Microsoft MVP in Hyper-V I can build bridges to make sure both worlds understand each other better and we, the customers get their needs served better.

Dell Enterprise Forum EMEA 2014 - Frankfurt

I’m happy I managed to go and I have some people to thank for me being able to grab this opportunity:

  • I cleared the time with my employer. This is great, this is a win win situation and I invested weekend time & extra hours for both my employer and myself.
  • I got an invite for the customer storage council where we learned a lot and got ample of opportunity to give honest and constructive feedback directly to the people that need to hear it! Awesome.
  • The DELL TechCenter Rockstar program invited me very generously to come over at zero cost for the Enterprise Forum. Which is great and helped my employer  and myself out. So, thank you so much for helping me attend. Does this color my judgment? 100%  pure objectivity does not exist but the ones who know me also know I communicate openly and directly. Look, I’ve never written positive reviews for money or kickbacks. I do not have sponsoring on my blog, even if that could help pay for conferences, travel expenses or lab equipment. Some say I should but for now I don’t. I speak my mind and I have been a long term DELL customer for some very good reasons. They deliver the best value for money with great support in a better way and model than others out there. I was sharing this info way before I became a Rockstar and they know that I tell the good, the bad and the ugly. They can handle it and know how to leverage feedback better than many out there.
  • Stijn Depril ( @sdepril, http://www.stijnsthoughts.be/), Technical Datacenter Sales at RealDolmen gave me a ride to Frankfurt and back home. Very nice of him and a big thank you for doing so.  He didn’t have to and I’m not a customer of them. Thank buddy, I appreciate it and it was interesting ton learn the partners view on things during the drive there and back. Techies will always be checking out gear …

Dell Enterprise Forum EMEA 2014 - Frankfurt

What did all this result in? Loads of discussion, learning and sharing about storage, networking, compute, cloud, futures and community in IT. It was an 18 hour per day technology fest in a very nice and well arranged fashion.

I was able to meet up with community members, twitter buddies, DELL Employees and peers from all over EMEA and share experiences, learn together, talk shop, provide feedback and left with a better understanding of the complexities and realities they deal with on their side.

Dell Enterprise Forum EMEA 2014 - Frankfurt

It has been time very well spent. I applaud DELL to make their engineers and product managers available for this event. I thank them for allowing us this amount of access to their brains from breakfast till the moment we say goodnight after a night cap. Well done, thank you for listening and I hope to continue the discussion. It’s great to be a DELL TechCenter Rockstar and work in this industry during this interesting times. To all the people I met again or for the first time, it was a great week of many interesting conversations!

For some more pictures and movies visit the Dell Enterprise Forum EMEA 2014 from Germany photo album on Flickr

Exchange 2010 SP3 Rollup 5 Added Support for Windows Server 2012 R2 Active Directory


6 weeks ago (February 25th 2014) Microsoft finally took away the last barrier to upgrading some of our Windows Server 2012 Active Directory Environments to R2.  Most of them are still running Exchange 2010 SP3 and not Exchange 2013. The reason is that Exchange 2013 was not deployed is whole other discussion Eye rolling smile.

However that dis mean that until the release of  Exchange Server 2010 SP3 Update Rollup 5 last month we could not upgrade Active Directory to Windows Server 2012 R2. Rollup 5 brought us support for exactly that. We can now:

  • Support Domain Controllers running Windows Server 2012 R2
  • Raise the Active Directory Forest Function Level and Domain Functional Level to Windows Server 2012 R2

Please note that you cannot deploy Exchange Server 2010 (SP3 RU5) on Windows Server 2012 R2 and you’ll probably never will be able to do that. I’m not sure Microsoft has any plans for this.

Now our office moves have been concluded, meaning I can get back to IT Infrastructure instead of being an glorified logistics & facility peon, we’re doing the upgrade.

This also means we can move the Active Directory environments to the latest version so we have the best possible position for any future IT projects at very low risk. The environments are already at W2K12 functional level. If the budgets get so tight they lose/scrap EA or volume licensing it also allows them to run at this level for many years to come without causing any blocking issues.

The Hyper V Amigos Showcast Episode 2: Unmap


We’re back for our second episode of the Hyper-V Amigos show cast. In this episode we discuss and demonstrate UNMAP in Windows Server 2012 R2 a bit. As always it was fun to work with Carsten Rachfahl.

2 Hyper-V Amigos having fun discussing UNMAP

 

Here’s our fun and unscripted (other than the PowerShell used in the demos) attempt at showing you UNMAP behavior with Hyper-V and a DELL Compellent SAN

If you want to read more on our experiences with UNMAP search my blog https://workinghardinit.wordpress.com/tag/unmap/. I have prepared some links for you.

I still need to get the slides uploaded, but all that info is in the blog posts.

Enjoy!

EDIT:

In relation to the question below about not much difference between Dynamically expanding VHD/VHDX. That demo didn’t work out so well here so I include  some screenshots of a comparison I just ran:

This is the dynamically expanding VHDX. on an IDE controller, no ODX.

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This is the dynamically expanding VHD on an vSCSI controller, with ODX.

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So yes, losing ODX makes things slower for dynamically expanding VHDX, but it still beats a Dynamically expanding VHD that has ODX.  A VHDX is a lot better at dynamically growing than a VHD.

Speaking At The ITPROceed Event–June 12th 2014, ALM Antwerp


The Belgian IT Pro community is organizing the ITPROceed event a “technology geek fest” as they call it on their web site.

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It’s a joint venture between the IT pro community and Microsoft Belgium to help you all proceed in designing, deploying and operating Microsoft technologies.

The sessions will not only help you proceed but succeed as well. The speakers are Microsoft MVPs, MEET members & passionate community experts. They’ll share expertise & information gather by using these technologies in real life deployments.

A rich mix of technologies you have available and need today will be discussed like the Cloud OS, System Center, SQL, Office 365, Windows 8, Unified Communications, Lync, Azure and SharePoint.

I’m speaking

I’ll be speaking about the features in Windows Server 2012 R2 that make it “The Scalable & Capable Cloud OS”.

Come see how you can leverage the capabilities of Windows Server 2012 R2, a true cloud OS, to achieve powerful and scalable solutions. We’ll demonstrate how to use technologies as SMB Direct, DVMQ/vRSS, ODX, UNMAP, VHDX and Storage QoS. This will help you get the most out of commodity infrastructure and investment in Windows today.  We’ll share our experiences with you based on real life deployments to help you proceed and succeed.

Join us!

Really, make time in your schedule and attend this event by registering here.

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Attend the sessions, talk shop with your peers and discuss your questions with the experts. I’ll see you there.

Windows NLB On Windows Server 2012 R2 Hyper-V: A Personal Preferred Configuration Using IGMP With Multicast


To know and see the issues we are dealing with in this demo, you need to read this blog post first: Windows NLB Nodes “Misconfigured” after Simultaneous Live Migration on Windows Server 2012 (R2).

We were dealing with some issues on on several WNLB clusters running on a Windows Server 2012 R2 Hyper-V cluster after a migration from an older cluster. So go read that and come back Smile.

Are you back? Good.

Let’s look at the situation we’ll use to show case one possible solution to the issues. If you have  a 2 node Hyper-V cluster, are using NIC Teaming for the switch and depending on how teaming is set up you’ll might run into these issues. Here we’ll use a single switch to mimic a stacked one (the model available to me is non stackable and I have only one anyway).

  • Make sure you enable MAC Spoofing on the appropriate vNIC or vNICs in the advanced settings

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  • Note that there is no need to use a static MAC address or copy your VIP mac into the settings of your VM  with Windows Server 2012 (R2) Hyper-V
  • Set up WNLB with IGMP multicast as option. While chancing this there will be some advice warnings thrown at you Smile

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I’m not going in to the fact that since W2K8 the network default configurations are all about security. You might have to do some configuration work to get the network flow to do what it needs to do. Lots on this  weak host/strong host model behavior on the internet . Even wild messy ramblings by myself here.

On to the switch itself!

Why IGMP multicast? Unicast isn’t the best option and multicast might not cut it or be the best option for your environment and IGMP is less talked about yet it’s a nice solution with Windows NLB, bar replacing into with a hardware load balancer. For this demo I have a DELL PowerConnect 5424 at my disposal. Great little switch, many of them are still serving us well after 6 years on the job.

What MAC address do I feed my switch configurations?

Ah! You are a smart cookie, aren’t you. A mere ipconfig reveals only the unicast MAC address of the NIC. The GUI on WNLB shows you the MAC address of the VIP. Is that the correct one for my chosen option, unicast, multicast or IGMP multicast?  No worries, the GUI indeed shows the one you need based on the WNLB option you configure. Also, take a peak at nlb.exe /? and you’ll find a very useful option called ip2mac.

Let’s run that against our VIP:

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And compare it to what we see in the GUI, you’ll notice that show the MAC to use with IGMP multicast as well.

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You might want to get the MAC address before you configure WNLB from unicast to IGMP multicast. That’s where the ip2mac option comes in handy.

Configuring your switch(es)

We have a multicast IP address that we’ll convert into the one we need to use. Most switches like the PowerConnect 5424 in the example will do that for you by the way.

I’m not letting the joining of the members to the Bridge Multicast Group happen automatically so I need to configure this. I actually have to VLANs, each Hyper-V host has 2 LACP NIC team with Dynamic load balancing connected to an LACP LAGs on this switch (it’s a demo, yes, I know no switch redundancy).  I have tow as some WNLB nodes have multiple clusters and some of these are on another VLAN.

I create a Bridge Multicast Group. For this I need the VLAN, the IGMP multicast MAC address and cluster IP address

When I specify the IGMP multicast MAC I take care to format it correctly with “:” instead of “–“ or similar.

You can type in the VIP IP address or convert is per this KB yourself. If you don’t the switch will sort you out.

The address range of the multicast group that is used is 239.255.x.y, where x.y corresponds to the last two octets of the Network Load Balancing virtual IP address.

For us this means that our VIP of 172.31.3.232 becomes 239.255.3.232. The switch handles typing in either the VIP or the converted VIP equally well.

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This is what is looks like, here there are two WNLB clusters in ICMP multicast mode configured. There are more on the other VLAN.

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We leave Bridge Multicast Forwarding here for what it is, no need in this small setup. Same for IGMP Snooping. It’s enable globally and we’ve set the members statically.

We make unregistered multicast is set to forwarding (default).

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Basically, we’re good to go now. Looking at the counters of the interfaces & LAGs you should see that the multicast traffic is targeted at the members of the LAGs/LAGs and not all interfaces of the switch. The difference should be clear when you compare the counters adding up before and after you configured IGMP.

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The Results

No over the top switch flooding, I can simultaneously live migrate multiple WLNB nodes and have them land on the same switch without duplicate IP address warning. Will this work for you. I don’t know. There are some many permutations that I can’t tell you what you should do in your particular situation to make it work well. I’ll just quote myself from my previous blog post on this subject:

“"If you insist you want my support on this I’ll charge a least a thousand Euro per hour, effort based only. Really. And chances are I’ll spend 10 hours on it for you. Which means you could have bought 2 (redundancy) KEMP hardware NLB appliances and still have money left to fly business class to the USA and tour some national parks. Get the message?”

But you have seen some examples on how to address issues & get a decent configuration to keep WNLB humming along for a few more years. I really hope it helps out some of you struggling with it.

Wait, you forgot the duplicate IP Address Warning!

No, I didn’t. We’ll address that here. There are some causes for this:

  • There is a duplicate IP address. If so, you need to address this.
  • A duplicate IP address warning is to be expected when you switch between unicast and multicast NLB cluster modes (http://support.microsoft.com/kb/264645). Follow the advice in the KB article and clearing the ARP tables on the switches can help and you should get rid of it, it’s transient.
  • There are other cause that are described here Troubleshooting Network Load Balancing Clusters. All come down to the fact that somehow you’re getting multiple MAC address associated with the same IP address. One possible cause can be that you migrated form an old cluster to a new cluster, meaning that the pool of dynamic IP addresses is different and hence the generated VIP MAC … aha!
  • Another reason, and again associated multiple MAC address associated with the same IP address is that you have an old static ARP entry for that IP address somewhere on your switches. Do some house cleaning.
  • If all the above is perfectly fine and you’re certain this is due to some Hyper-V live migration, vSwitch, firmware, driver bug you can get rid of the warning by disabling ARP checks on the cluster members. Under HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters, create a DWORD value with as name “ArpRetryCount” and set the value to 0. Reboot the server for this to take effect. In general this is not a great idea to do. But if you manage your IP addresses well and are sure no static entries are set on the switch it can help avoid this issue. But please, don’t just disable “ArpRetryCount” and ignore the root causes.

Conclusion

You can still get WNLB to work for you properly, even today in 2014. But it’s time to start saying goodbye to Windows NLB. The way the advanced networking features are moving towards layer 3 means that “useful hacks” like MAC spoofing for Windows NLB are going no longer going to work.  But until you have implement hardware load balancing I hope this blog has given you some ideas & tips to keep Windows NLB running smoothly for now. I’ve done quite few and while it takes some detective work & testing, so far I have come out victorious. Eat that Windows NLB! I have always enjoyed making it work where people said it couldn’t be done. But with the growing important of network virtualization and layer 3 in our networks, this nice hack, has had it’s time.

For some reasons developers like Windows NLB as  “it’s easy and they are in control as it runs on their servers”. Well … as you have seen nothing comes free and perhaps our time is better spend in some advanced health checking and failover in hardware load balancing. DevOps anyone?

Windows NLB Nodes Misconfigured after Simultaneous Live Migration on Windows Server 2012 (R2)


Here’s the deal. While Windows NLB on Hyper-V guests might seem to work OK you can run into issues. Our biggest challenge was to keep the WNLB cluster functional when all or multiple node of the cluster are live migrated simultaneously. The live migration goes blazingly fast via SMB over RDMA nut afterwards we have a node or nodes in an problematic state and clients being send to them are having connectivity issues.

After live migrating multiple or all nodes of the Windows NLB cluster simultaneously the cluster ends up in this state:

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A misconfigured interface. If you click on the error for details you’ll see

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Not good, and no we did not add those IP addresses manually or so, we let the WNLB cluster handle that as it’s supposed to do. We saw this with both fixed MAC addresses (old school WNLB configuration of early Hyper-V deployments) and with dynamic MAC addresses. On all the nodes MAC spoofing is enabled on the appropriate vNICs.

The temporary fix is rather easy. However it’s a manual intervention and as such not a good solution. Open up the properties of the offending node or nodes (for every NLB cluster that running on that node, you might have multiple).

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Click “OK” to close it …

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… and you’re back in business.

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Scripting this out somehow with nlb.exe or PowerShell after a guest gets live migrated is not the way to go either.

But that’s not all. In some case you’ll get an extra error you can ignore if it’s not due to a real duplicate IP address on your network:

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We tried rebooting the guest, dumping and recreating the WNLB cluster configuration from scratch. Clearing the switches ARP tables. Nothing gave us a solid result.

No you might say, Who live migrates multiple WNLB nodes at the same time? Well any two node Hyper-V cluster that uses Cluster Aware Updating get’s into this situation and possibly bigger clusters as well when anti affinity is not configured or chose to keep guest on line over enforcing said anti affinity, during a drain for an intervention on a cluster perhaps etc. It happens. Now whether you’ll hit this issue depends on how you configure and use your switches and what configuration of LBFO you use for the vSwitches in Hyper-V.

How do we fix this?

First we need some back ground and there is way to much for one blog actually. So many permutations of vendors, switches, configurations, firmware & drivers …

Unicast

This is the default and Thomas Shinder has an aging but  great blog post on how it works and what the challenges are here. Read it. It you least good option and if you can you shouldn’t use it. With Hyper-V we and the inner workings and challenges of a vSwitch to the mix. Basically in virtualization Unicast is the least good option. Only use it if your network team won’t do it and you can’t get to the switch yourself. Or when the switch doesn’t support mapping a unicast IP to a multicast MAC address. Some tips if you want to use it:

  1. Don’t use NIC teaming for the virtual switch.
  2. If you do use NIC teaming for the virtual switch you should (must):
    • use switch independent teaming on two different switches.
    • If you have a stack or just one switch use multicast or even better IGMP with multicast to avoid issues.

I know, don’t shout at me, teaming on the same switch, but it does happen. At least it protects against NIC issues which are more common than switch or switch port failures.

Multicast

Again, read Thomas Shinder his great blog post on how it works and what the challenges are here.

It’s an OK option but I’ll only use it if I have a switch where I can’t do IGMP and even then I do hope I can do two things:

  1. Add a static entry for the cluster IP address  / MAC address on your switch if it doesn’t support IGMP multicast:
    • arp [ip] [cluster multicast mac*] ARPA  > arp 172.31.1.232  03bf.bc1f.0164 ARPA
  2. To prevent switch flooding occurs, as with the unicast configure your switch which ports to use for multicast traffic:
    • mac-address-table static [cluster multicast mac] [vlan id] [interface]  > mac-address-table static 03bf.bc1f.0164 vlan 10 interface Gi1/0/1

The big rotten thing here is that this is great when you’re dealing with physical servers. They don’t tend to jump form switch port to switch port and switch to switch on the fly like a virtual machine live migrating. You just can’t hardcode all the vSwitch ports into the physical switches, one they move and depending on the teaming choice there are multiple ports, switches etc …it’s not allowed and not possible. So when using multicast in a Hyper-V environment stick to 1). But here’s an interesting fact. Many switches that don’t support 1) do support 2). Fun fact is that most commodity switches do seems to support IGMP … and that’s your best choice anyway! Some high end switches don’t support WNLB well but in that category a hardware load balancer shouldn’t be an issue. But let’s move on to my preferred option.

  • IGMP With Multicast (see IGMP Support for Network Load Balancing)

    This is your best option and even on older, commodity switches like a DELL PowerConnect 5424 or 5448 you can configure this. It was introduced in Windows Server 2003 (did not exist in NT4.0 or W2K). It’s my favorite (well, I’d rather use hardware load balancing) in a virtual environment. It works well with live migration, prevents switch flooding and with some ingenuity and good management we can get rid of other quirks.

    So Didier, tell us, how to we get our cookie and eat it to?

    Well, I will share the IGMP with Multicast solution with you in a next blog. Do note that as stated above there are some many permutations of Windows, teaming, WNL, switches  & firmware/drivers out there I give no support and no guarantees. Also, I want to avoid writing a  100 white paper on this subject?. If you insist you want my support on this I’ll charge at least a thousand Euro per hour, effort based only. Really. And chances are I’ll spend 10 hours on it for you. Which means you could have bought 2 (redundancy) KEMP hardware NLB appliances and still have money left to fly business class to the USA and tour some national parks. Get the message?

    But don’t be sad. In the next blog we’ll discuss some NIC teaming for the vSwitch, NLB configuration with IGMP with Multicast and show you a simple DELL PowerConnect 5424 switch example that make WNLB work on a W2K12R2 Hyper-V cluster with NIC teaming for the vSwitch and avoids following issues:

    • Messed up WNLB configuration after the simultaneous live migration of all or multiple NLB Nodes.
    • You avoid “false” duplicate IP address goof ups (at the cost of  IP address hygiene management).
    • You prevent switch port flooding.

    I’d show you on redundant Force10 S4810 but for that I need someone to ship me some of those with SFP+ modules for the lab, free of cost for me to keep Winking smile

    Conclusion

    It’s time to start saying goodbye to Windows NLB. The way the advanced networking features are moving towards layer 3 means that “useful hacks” like MAC spoofing for Windows NLB are going no longer going to work.  But until you have implement hardware load balancing I hope this blog has given you some ideas & tips to keep Windows NLB running smoothly for now. I’ve done quite few and while it takes some detective work & testing, so far I have come out victorious. Eat that Windows NLB!