Questions[client-server](server)

The client always communicates using TLS 1.0 , On the Client side, I am having Windows Server 2012 R2 ( which as per the documentation it supports TLS 1.2 ) After going through many forums I realized that adding below registry entry might help.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001

But still, the protocol client first contacts server is with TLS 1.0.

client-side configurations are as below:

Windows Server 2012 R2 .NET httpRuntime targetFramework="4.5.2" .NET Version=4.0.30319.42000 32bit ( I assume this means it is on .NET framework 4.5.2)

Also, I tried adding the below code to App.config and Web.config files.

**Web.config**
    <appSettings>
       <add name="AppContext.SetSwitch:Switch.System.Net.DontEnableSystemDefaultTlsVersions" value="false" />
    </appSettings> 

**App.config**
    <appSettings>
    <AppContextSwitchOverrides value="Switch.System.ServiceModel.DisableUsingServicePointManagerSecurityProtocols=false;Switch.System.Net.DontEnableSystemDefaultTlsVersions=false" />
    </appSettings>

What can be the possible reason for the client using TLS 1.0 during the initial handshake with Server? and how to make sure the client always tries to communicate with TLSv1.2 without disabling TLS 1.0 ?

In SCCM - when I add a computer to the Devices and then to a custom device collection, it takes a long time for it to show up in the Custom Device Collection. Is there a way to manipulate this time? I'm assuming that SCCM is goes through a refresh period and when it notices a change, it adds the systems accordingly, or maybe I'm completely wrong on how that works and it's actually doing something else.

Simply put, I'd like for the computer to be added to the Custom Device Collection immediately, how can I accomplish this?

we have strange situation with our client-server platform. On filed we have 10 clients with same firmware version but on different networks. Client sends 50 bytes of payload to server every 15sec. Clients are connected behind NAT and everything works perfectly fine except for one client. TcpVIew software shows that particular client as in SNY_RCVD state.

After 1-3 days we got into trouble because client is unable to reconnect with server. On server we have WCF service, basic TCP listener. The thing is that client doesn't even reach our server software because it is unable to connect with OS socket layer (windows Server 2012).

We applied "Hardening TCP Stack" guidelines from MS but it doesn't help. We tried to restart Server several times - it doesn't help.

Here is wireshark capture and if anyone can figure out what's happening or even give us some direction...

Thank you.

wireshark capture

TcpView

I want to know the difference between cloud computing and client server architecture. I mean how is cloud computing different from a website that provides me some services. And what is the meaning of elasticity in terms of cloud computing.

Even though I am fully aware that versions of this question have been asked googol number of times, I'll try not to repeat them.

I have many sets of many files (some files are small, but some are large, like, ~10-20GB). I have multiple servers, each one can host one or more of those sets of files. Of course, one server can host 50% of total number of sets, and other 50% can host another number of sets.

You can think of set as of collection of large media files, really big image libraries, complete applications, whatever, it doesn't really matter, as long as there are large files in the set.

Server can update its copy of set at any point in time (either by replacing files in the set with completely new files, or by applying patches to some of files, which would result in having almost same files with only slight differences).

On the other side, I have many clients, who should be able to obtain any given set (or multiple sets) from servers, and keep their copies of sets up-to-date (synchronized) with sets on server, whenever one wants to use the set.

The tools that I have considered are following:

• rsync -- It's great for syncing many small-to-medium-sized files, but not so ideal when syncing large files, as it uses algorithm which reads entire file at both sides in order to determine if file should be copied or not. This is okay when file should be copied for the first time, or when file is completely changed, but not-so-okay, when, say, only 1% of 10GB file is changed.
• SVN -- It's great when it comes to finding differences and transferring only those deltas around, but I'm not so sure how optimal it is when it comes to disk usage (will entire set be twice as big on both client and server, due to once set is stored in repository?).
• Torrent -- This one could be feasible, distribution-wise. For instance, create a torrent for each set on server, start seeding it there, and clients that receive those sets also continue to seed to other clients, thus distributing the load across every computer that holds copy of set. However, I'm not sure if it would be able to somehow distribute differences, once set on server gets changed... Would it require creation of new torrent for each change? Also, I don't know how torrent would behave in local network, speed-wise (could it be able to transfer files between one server and one client at maximum, network-limited speed. or it adds some serious protocol overhead? How about network congestion?)
• Custom solution. Well, not much to add here, but that it would most likely be re-inventing the wheel, and that some existing solution would most likely fit my needs, if I was only aware of it.

So, the question is: what method of distribution/synchronization (utilities, approach) would be best suited for my situation?