System.Net Namespace Blog

Occasionally one can find weblogs devoted to useful things on the blogosphere like System.Net namespace blog.

You know, there are things like HttpWebRequest and other useful classes in the namespace. There are some new classes in .Net 2.0 like FtpWebRequest. Subscribed.

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Hi Anatoly,
Common cause of error "can not create secure connection" is error in server certificate validation, but note that there might be other reasons too, if you can send me more detailed about your scenario I could help (with email address would be appreciated).

If it is certificate error issue, check MSDN sample for System.Net.ICertificatePolicy, you could write your own custom certificate validation policy.

Thanks,

Hi

The issue is solved and everything works ok now.
The issue you are talking about is the most common issue and can be solved this way: http://blogs.x2line.com/al/articles/258.aspx
ICertificatePolicy is the first thing people think about, but it was not it.

My problem was different. The problem was throwing inconsistent errors of: "The underlying connection was closed: Could not establish secure channel for SSL/TLS" connecting to the remote server via https; our client is asp.net application. Although if you Google this issue - there are lots of people having the same problem without finding any solution. I've spent a lot time on this.

Solution:
Setting KeepAlive property to false of HttpWebRequest solves entirely the issue. It seems that there is some leak of connections despite the fact that the underlying streams are closed properly and HttWebResponse is closed explicitly, too. The main difficulty that the problem is inconsistent and 95% of the time everything worked properly.

Also I know now that one should use HttWebRequest/HttpWebResponse and not WebRequest/WebResponse because it is more reliable, at least if you google it there are lots of issues of inconsistent behaviour. The same is about WebClient since it uses WebRequest, you can see it in Reflector.

thanks.

anyway my mail address is anatolyl at gmail.com

Anatoly,

I was experiencing the same exact problem. Although, in my situation for a specific URL it would always fail, where it would work for other secure URL's.

You are right about the keepalive, but it didn't work at first. I had to spend another couple of hours researching and found that I also have to change the version, and then it worked. You don't have to add a client cert or anything else I've seen, just make these two changes:

moHttpRequest.KeepAlive = False
moHttpRequest.ProtocolVersion = HttpVersion.Version10

Exception:
"The underlying connection was closed: Could not establish secure channel for SSL/TLS."

Inner Exception:
"The request was aborted: The connection was closed unexpectedly."

Thanks, Justin

I am using a WSDL generated proxy (changed to inherit WebServicesClientProtocol) to post to the web server. I did the following to hopefully correct the problem with intermittent errors (The underlying connection was closed: Could not establish secure channel for SSL/TLS)

Protected Overrides Function GetWebRequest(ByVal uri As
Dim myWebRequest As WebRequest = MyBase.GetWebRequest(uri)
Dim myPropertyInfo As PropertyInfo = myWebRequest.GetType().GetProperty("Request")
Dim myHTTPWebRequest As HttpWebRequest = CType(myPropertyInfo.GetValue(myWebRequest, Nothing), HttpWebRequest)
myHTTPWebRequest.KeepAlive = False
myHTTPWebRequest.ProtocolVersion = HttpVersion.Version10
Return myWebRequest
End Function

This did not entirely work. I have posted 450,000 times and have received the error 3 times. It seems the KeepAlive/ProtocolVersion settings help the problem but dont cure it.

Wang:

I don't understand your function signature. May be something is missing ? I advice to set explicitly MaximumAutomaticRedirections like this:

request1.MaximumAutomaticRedirections = 40;

don't set explicitly ProtocolVersion (I didn't talk about it here). that's it.

In any case 3 errors in 450000 attempts sounds like a very good result to me :)

Hope this helps.
Anatoly

Hey guys, I am having a problem here with SSL / TLS: Could not establish secure channel for SSL/TLS.

I've checked the IIS logs and this coincides with a HTML 400 Bad Request. The funny thing is that 90% of the time, the request works, it only fails when sending one particular set of data. Is my problem data related?