I want to implement an WCF-Service that uses an TCP transport layer secured by TLS/SSL and still use windows authentication(kerberos/NTLM) on the server to identify the calling client.
The part with the windows authentication already works but I'm not sure if the connection is encrypted.
I'm using a NetTcpBinding and create it like this:
var binding = new NetTcpBinding()
{
ReceiveTimeout = TimeSpan.FromMinutes(30),
OpenTimeout = TimeSpan.FromMinutes(1),
CloseTimeout = TimeSpan.FromSeconds(30),
MaxReceivedMessageSize = int.MaxValue,
ReliableSession =
{
Enabled = true,
InactivityTimeout = TimeSpan.FromMinutes(1)
},
Security =
{
Mode = SecurityMode.Transport,
Transport =
{
ClientCredentialType = TcpClientCredentialType.Windows,
ProtectionLevel = ProtectionLevel.EncryptAndSign,
SslProtocols = SslProtocols.Tls12
}
}
};
I already sniffed some packages with wireshark and found the following in one of the first packages: "application/negotiate".
I just want to be 110% sure the connection is encrypted with TLS but I'm not because i don't know how to check for it.
Client certificates are not possible in my environment.
Please dont just paste a link to some microsoft-website on how to set things up.
There is no example that shows how to use both windows auth and TLS.
The application is standalone, so there is no IIS or something!
Any help is appreciated!
This is example for Net.Tcp binding with transport security and standalone hosting: https://learn.microsoft.com/en-us/dotnet/framework/wcf/feature-details/transport-security-with-windows-authentication
It has almost exact configuration as you do. The only exception is that you add reliable sessions (this does not affect security at all) and limit available SSL protocols to Tls12 only (default value is Ssl3 | Tls | Tls11 | Tls12). So, it's still secure.
So, the answer is: yes, it is secured.
Recently i asked to implement a wcf service.
One of the problems i am facing is how to detect network failure and raise fault exception,
after some research , i found that is it possible to set receive time out property to max value,
and the inactivity to some time span,
basically it works, but my question is am i doing good practice while i doing so?
or anybody have a better way to detect unexpected network failure
I am using tcp binding option
netTcpBind.ReceiveTimeout = TimeSpan.MaxValue;
netTcpBind.CloseTimeout = TimeSpan.MaxValue;
netTcpBind.SendTimeout = TimeSpan.MaxValue;
netTcpBind.ReliableSession.Enabled = true;
netTcpBind.ReliableSession.InactivityTimeout = new TimeSpan(0,2,0);
ReliableSession internally sends infrastructure messages in the specified time interval & verifies whether the TCP session is still alive. This should handle all network related failure errors. Check the below link for details:
http://www.blogs.sigristsoftware.com/marcsigrist/post/Prerequisits-for-implementing-a-keep-alive-mechanism-in-WCF-30.aspx
I have a WCF service hosted by a Windows Service. It has a Publish/Subscribe relationship to zero to many clients within the network. The binding is net.TCP. The WCF Service provides a "Subscribe" method to the client so the client can register a callback handler. The WCF Service periodically calls methods in the callback handler of any currently subscribed clients.
The interface is defined (with abreviation) below:
[OperationContract(IsOneWay = false)]
void ReturnInitialData(
InitialData initialData,
CraneState recentState,
VerticalCraneState recentVerticalCraneState,
ThresholdState recentThresholdState,
StationaryStatusFlagsState recentStationaryStatusFlagState,
LightsState recentLights,
BarrierRiskState recentBarrierRiskState
);
When the service calls ReturnInitialData() with approximately 42000 bytes of data, it works fine. When the service calls it with approximately 70000 bytes of data it throws the following exception:
The socket connection was aborted. This could be caused by an
error processing your message or a receive timeout being
exceeded by the remote host, or an underlying
network resource issue. Local socket timeout was '00:10:00'.
This is the netTcpBinding configuration:
General
CloseTimeout 00:00:20
HostNameComparisonMode StrongWildcard
ListenBacklog 0
MaxBufferPoolSize 524288
MaxBufferSize 2147483647
MaxConnections 0
MaxReceivedMessageSize 2147483647
OpenTimeout 00:01:00
PortSharingEnabled False
ReceiveTimeout 00:10:00
SendTimeout 00:10:00
TransactionFlow False
TransactionProtocol Ole Transactions
TransferMode Buffered
ReaderQuotas Properties
MaxArrayLength 0
MaxBytesPerRead 0
MaxDepth 0
MaxNameTableCharCount 0
MaxStringContentLength 0
ReliableSession Properties
Enabled False
InactivityTimeout 00:10:00
Ordered True
Any leads or pointers are welcome.
adkSerenity and shambulator,
Thank you. I found the problem. It turned out to be a buffer size. I was pretty sure it wasn't a timeout because the shortest timeout was set to one minute and I could reproduce the error in thirty seconds.
I had been avoiding WCF Tracing and Message Logging because it was so intimidating. So much to read, so little time. ;-}
When I generated the output at looked at it with the viewer, it might as well have been Martian. After studying it for a while in a fog, I finally get the impression that the loss of communication was not the fault of the service. Then the light bulb went on and I checked the client's config file. Sure enough, the MaxBufferSize was set to 65535, effectively cutting off the 70000 byte message.
Thanks again for pointing me in the right direction.
You may want to enable WCF Tracing and Message Logging, which will allow you to monitor/review communication to/from the WCF service and hopefully isolate the issue (which, based on the provided error message, may likely be a timeout issue.)
The following links provide a good overview:
http://msdn.microsoft.com/en-us/library/ms733025.aspx
Regards,
I have a server app and sometimes, when the client tries to connect, I get the following error:
NOTE: the "couldn't get stream from client or login failed" is a text that's added by me in catch statement
and the line at which it stops ( sThread : line 96 ) is :
tcpClient = (TcpClient)client;
clientStream = tcpClient.GetStream();
sr = new StreamReader(clientStream);
sw = new StreamWriter(clientStream);
// line 96:
a = sr.ReadLine();
What may be causing this problem? Note that it doesn't happen all the time
I received this error when calling a web-service. The issue was also related to transport level security. I could call the web-service through a website project, but when reusing the same code in a test project I would get a WebException that contained this message. Adding the following line before making the call resolved the issue:
System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;
Edit
System.Net.ServicePointManager.SecurityProtocol - This property
selects the version of the Secure Sockets Layer (SSL) or Transport
Layer Security (TLS) protocol to use for new connections that use the
Secure Hypertext Transfer Protocol (HTTPS) scheme only; existing
connections are not changed.
I believe the SecurityProtocol configuration is important during the TLS handshake when selecting the protocol version.
TLS handshake - This protocol is used to exchange all the information required by both sides for the exchange of the actual application data by TLS.
ClientHello - A client sends a ClientHello message specifying the highest TLS protocol version it supports ...
ServerHello - The server responds with a ServerHello message, containing the chosen protocol version ... The chosen protocol version should be the highest that both the client and server support. For example, if the client supports TLS version 1.1 and the server supports version 1.2, version 1.1 should be selected; version 1.2 should not be selected.
This error usually means that the target machine is running, but the service that you're trying to connect to is not available. (Either it stopped, crashed, or is busy with another request.)
In English:
The connection to the machine (remote host/server/PC that the service runs at) was made but since the service was not available on that machine, the machine didn't know what to do with the request.
If the connection to the machine was not available, you'd see a different error. I forget what it is, but it's along the lines of "Service Unreachable" or "Unavailable".
Edit - added
It IS possible that this is being caused by a firewall blocking the port, but given that you say it's intermittent ("sometimes when the client tries to connect"), that's very unlikely. I didn't include that originally because I had ruled it out mentally before replying.
My specific case scenario was that the Azure app service had the minimum TLS version changed to 1.2
I don't know if that's the default from now on, but changing it back to 1.0 made it work.
You can access the setting inside "SSL Settings".
According to "Hans Vonn" replies.
Adding the following line before making the call resolved the issue:
System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;
After adding Security protocol and working fine but I have to add before every API call which is not healthy. I just upgrade .net framework version at least 4.6 and working as expected do not require to adding before every API call.
Not sure which of the fixes in these blog posts helped, but one of them sorted this issue for me ...
http://briancaos.wordpress.com/2012/07/06/unable-to-read-data-from-the-transport-connection-the-connection-was-closed/
The trick that helped me was to quit using a WebRequest and use a HttpWebRequest instead. The HttpWebRequest allows me to play with 3 important settings:
and
http://briancaos.wordpress.com/2012/06/15/an-existing-connection-was-forcibly-closed-by-the-remote-host/
STEP 1: Disable KeepAlive
STEP 2: Set ProtocolVersion to Version10
STEP 3: Limiting the number of service points
For those who may find this later, after .NET version 4.6, I was running into this problem as well.
Make sure that you check your web.config file for the following lines:
<compilation debug="true" targetFramework="4.5">
...
<httpRuntime targetFramework="4.5" />
If you are running 4.6.x or a higher version of .NET on the server, make sure you adjust these targetFramework values to match the version of the framework on your server. If your versions read less than 4.6.x, then I would recommend you upgrade .NET and use the newer version unless your code is dependent on an older version (which, in that case, you should consider updating it).
I changed the targetFrameworks to 4.7.2 and the problem disappeared:
<compilation debug="true" targetFramework="4.7.2">
...
<httpRuntime targetFramework="4.7.2" />
The newer frameworks sort this issue out by using the best protocol available and blocking insecure or obsolete ones. If the remote service you are trying to connect to or call is giving this error, it could be that they don't support the old protocols anymore.
Calls to HTTPS services from one of our servers were also throwing the "Unable to read data from the transport connection : An existing connection was forcibly closed" exception. HTTP service, though, worked fine. Used Wireshark to see that it was a TLS handshake Failure. Ended up being that the cipher suite on the server needed to be updated.
This solved my problem. I added this line before the request is made:
System.Net.ServicePointManager.Expect100Continue = false;
It seemed there were a proxy in the way of the server that not supported 100-continue behavior.
This won't help for intermittent issues, but may be useful for other people with a similar problem.
I had cloned a VM and started it up on a different network with a new IP address but not changed the bindings in IIS. Fiddler was showing me "Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host" and IE was telling me "Turn on TLS 1.0, TLS 1.1, and TLS 1.2 in Advanced settings". Changing the binding to the new IP address solved it for me.
For some reason, the connection to the server was lost. It could be that the server explicitly closed the connection, or a bug on the server caused it to be closed unexpectedly. Or something between the client and the server (a switch or router) dropped the connection.
It might be server code that caused the problem, and it might not be. If you have access to the server code, you can put some debugging in there to tell you when client connections are closed. That might give you some indication of when and why connections are being dropped.
On the client, you have to write your code to take into account the possibility of the server failing at any time. That's just the way it is: network connections are inherently unreliable.
I was sending the HttpWebRequest from Console App, and UserAgent was
null by (default), so setting UserAgent worked along with setting
SecurityProtocol.
Should set SecurityProtocol before creating HttpWebRequest.
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
HttpWebRequest req = (HttpWebRequest)WebRequest.Create("yourpostURL");
req.UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36";
The webrequest user agent is null by default. Just google "block empty user agent" and you'll find a strong desire of many web server admins to do just that.
Sending my request with
request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:50.0) Gecko/20100101 Firefox/50.0";
fixed the issue.
I get that problem in the past. I'm using PostgreSQL and when I run my program, sometimes it connects and sometimes it throws an error like that.
When I experiment with my code, I put my Connection code at the very first line below the public Form. Here is an example:
BEFORE:
public Form1()
{
//HERE LIES SOME CODES FOR RESIZING MY CONTROLS DURING RUNTIME
//CODE
//CODE AGAIN
//ANOTHER CODE
//CODE NA NAMAN
//CODE PA RIN!
//Connect to Database to generate auto number
NpgsqlConnection iConnect = new NpgsqlConnection("Server=localhost;Port=5432;User ID=postgres;Password=pass;Database=DB");
iConnect.Open();
NpgsqlCommand iQuery = new NpgsqlCommand("Select * from table1", iConnect);
NpgsqlDataReader iRead = iQuery.ExecuteReader();
NpgsqlDataAdapter iAdapter = new NpgsqlDataAdapter(iQuery);
DataSet iDataSet = new DataSet();
iAdapter.Fill(iDataSet, "ID");
MessageBox.Show(iDataSet.Tables["ID"].Rows.Count.ToString());
}
NOW:
public Form1()
{
//Connect to Database to generate auto number
NpgsqlConnection iConnect = new NpgsqlConnection("Server=localhost;Port=5432;User ID=postgres;Password=pass;Database=DB");
iConnect.Open();
NpgsqlCommand iQuery = new NpgsqlCommand("Select * from table1", iConnect);
NpgsqlDataReader iRead = iQuery.ExecuteReader();
NpgsqlDataAdapter iAdapter = new NpgsqlDataAdapter(iQuery);
DataSet iDataSet = new DataSet();
iAdapter.Fill(iDataSet, "ID");
MessageBox.Show(iDataSet.Tables["ID"].Rows.Count.ToString());
//HERE LIES SOME CODES FOR RESIZING MY CONTROLS DURING RUNTIME
//CODE
//CODE AGAIN
//ANOTHER CODE
//CODE NA NAMAN
//CODE PA RIN!
}
I think that the program must read first the connection before doing anything, I don't know, correct me if I'm wrong. But according to my research, it's not a code problem - it was actually from the machine itself.
System.Net.ServicePointManager.Expect100Continue = false;
This issue sometime occurs due the reason of proxy server implemented on web server. To bypass the proxy server by putting this line before calling the send service.
We had a very similar issue whereby a client's website was trying to connect to our Web API service and getting that same message. This started happening completely out of the blue when there had been no code changes or Windows updates on the server where IIS was running.
In our case it turned out that the calling website was using a version of .Net that only supported TLS 1.0 and for some reason the server where our IIS was running stopped appeared to have stopped accepting TLS 1.0 calls. To diagnose that we had to explicitly enable TLS via the registry on the IIS's server and then restart that server. These are the reg keys:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS
1.0\Client] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS
1.0\Server] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS
1.1\Client] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS
1.1\Server] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001
[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
If that doesn't do it, you could also experiment with adding the entry for SSL 2.0:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Client]
"DisabledByDefault"=dword:00000000
"Enabled"=dword:00000001
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server]
"DisabledByDefault"=dword:00000000
"Enabled"=dword:00000001
My answer to another question here has this powershell script that we used to add the entries:
NOTE: Enabling old security protocols is not a good idea, the right answer in our case was to get the client website to update it's code to use TLS 1.2, but the registry entries above can help diagnose the issue in the first place.
The reason this was happening to me was I had a recursive dependency in my DI provider. In my case I had:
services.AddScoped(provider => new CfDbContext(builder.Options));
services.AddScoped(provider => provider.GetService<CfDbContext>());
Fix was to just remove the second scoped service registration
services.AddScoped(provider => new CfDbContext(builder.Options));
Had a similar problem and was getting the following errors depending on what app I used and if we bypassed the firewall / load balancer or not:
HTTPS handshake to [blah] (for #136) failed.
System.IO.IOException Unable to read data from the transport
connection: An existing connection was forcibly closed by the remote
host
and
ReadResponse() failed: The server did not return a complete response for this request. Server returned 0 bytes.
The problem turned out to be that the SSL Server Certificate got missed and wasn't installed on a couple servers.
For me, It was an issue where in the IIS binding it had the IP address of the web server.
I changed it to use all unassigned IPs and my application started to work.
I experienced the error with python clr running mdx query to Microsoft analytic services using adomd
I solved it with help of Hans Vonn and here is the python version:
clr.AddReference("System.Net")
from System.Net import ServicePointManager, SecurityProtocolType
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls
I received this error simply because I was attempting to make an http connection to an https-only server. Changing the request protocol in the URI from http to https thus resolved it.
This is how I solved the issue:
int i = 0;
while (stream.DataAvailable == true)
{
bytes[i] = ((byte)stream.ReadByte());
i++;
}
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
Console.WriteLine("Received: {0}", data);
I had a Third Party application (Fiddler) running to try and see the requests being sent. Closing this application fixed it for me
If you have a https certificate on the domain, make sure you have the https binding to the domain name in IIS.
In IIS -> Select your domain -> Click on Bindings
Site Bindings Window opens up. Add a binding for https.
Try checking if you can establish handshake in the first place. I had this issue before when uploading a file and I only figured out that the issue was the nonexistent route when I removed the upload and checked if it can login given the parameters.
Another option would be to check the error code generated using try-catch block and first catching a WebException.
In my case, the error code was "SendFailure" because of certificate issue on HTTPS url, once I hit HTTP, that got resolved.
https://learn.microsoft.com/en-us/dotnet/api/system.net.webexceptionstatus?redirectedfrom=MSDN&view=netframework-4.8
This problem occurring when the Service is Unavailable within the proxy server. We can bypass the proxy server.
Before start, the service, apply this code line.
System.Net.ServicePointManager.Expect100Continue = false;
Further details
In my case I resolved this problem setting a correct API's url in my application.
It was an error connection between the application and API.
I have written a WCF service. The client is built up in Silverlight.
It works fine, but as soon as the internet connection is lost even for a second, my application throws an error in a message box "the remote server returned an error not found"
Also, it sometimes thorws WCF Request Timed Out exception. All these exceptions are displayed in a message box. I wanted to know if there is a way to suppress these exceptions, as-in I don't want a message box to be popped up everytime with these messages.
Please give me some leads.
Thanks
Not sure about your first issue.
The second issue can be solved by two ways: 1.set up client side binding timeout to longer time in web.config 2.write code to set up binding timeout. The following example sets up BasicHttpBinding at code behind.
BasicHttpBinding binding = new BasicHttpBinding();
binding.ReceiveTimeout = System.TimeSpan.Parse("00:10:00");
binding.SendTimeout = System.TimeSpan.Parse("00:10:00");
you have to catch the Exception in the Catch block and there you can keep the process for the ideal state for some time.
After some time again try to access the remote services. This will how you can handle this.