Getting HTTP 400 errors with multithreaded webservice calls through an authenticating ISA proxy

[JohnH]

Hi,
In my application which has two or more threads calling web
service or just HttpWebRequest I am seeing some HTTP 400 errors retrun
in the response. All the calls are going through the same ISA proxy
the connections to which must be authenticated. The 400 error are
comming fron the wed server back through the proxy.

When I Sniff the connections I can see that the http message that is
causing the issue is one that is part of the challange respons
messages used to authenticate with the ISA proxy server. However it is
being sent to the ISA proxy server over a connection that is already
authenticated. As a result it is being forwarded on to the web server
which returns the 400 error.

The issue seems to be that when an existing authenticated connection
exsit and an atttempt is made to create another connection to the
proxy server the following can happen.
1. The first connection exist and is authenticated
2. The second connection is created and a request
without any authenication credentials is sent to the proxy
3. The Proxy reponses on second connection with a
407 that authentication is required.
4. Now the client send the request with Negotiate
authentication but over the first connection that is already
authenticated.
5. Now a HTTP 400 error is return in the response
on the first connection. This comes from the web server as it is not
expecting an proxy authentication.

Step 4 should (and usually is) sent over the second connection, which
would then continue with the several challange respone messages
authenticating the connection.

Notes:
1. With keep-alives ON this error occurs only a hand full of time a
day, while with keep-alive OFF it will happen within a couple of
minutes.
2. I am using .Net 2.0
3. Request are sent once a second

Has anyone seen this issue before? Is it an issue with how the
HttpWebRequest choose connection fron some http connection pool?

[Paula DiTallo]

Hi,
In my application which has two or more threads calling web
service or just HttpWebRequest I am seeing some HTTP 400 errors retrun
in the response. All the calls are going through the same ISA proxy
the connections to which must be authenticated. The 400 error are
comming fron the wed server back through the proxy.

When I Sniff the connections I can see that the http message that is
causing the issue is one that is part of the challange respons
messages used to authenticate with the ISA proxy server. However it is
being sent to the ISA proxy server over a connection that is already
authenticated. As a result it is being forwarded on to the web server
which returns the 400 error.

The issue seems to be that when an existing authenticated connection
exsit and an atttempt is made to create another connection to the
proxy server the following can happen.
1. The first connection exist and is authenticated
2. The second connection is created and a request
without any authenication credentials is sent to the proxy
3. The Proxy reponses on second connection with a
407 that authentication is required.
4. Now the client send the request with Negotiate
authentication but over the first connection that is already
authenticated.
5. Now a HTTP 400 error is return in the response
on the first connection. This comes from the web server as it is not
expecting an proxy authentication.

Step 4 should (and usually is) sent over the second connection, which
would then continue with the several challange respone messages
authenticating the connection.

Notes:
1. With keep-alives ON this error occurs only a hand full of time a
day, while with keep-alive OFF it will happen within a couple of
minutes.
2. I am using .Net 2.0
3. Request are sent once a second

Has anyone seen this issue before? Is it an issue with how the
HttpWebRequest choose connection fron some http connection pool?

Hi,
It looks like you need to install this hotfix might help you out:

http://support.microsoft.com/?kbid=924638

Your problem was probably happening because you weren't able to set the KeepAlive property to false when you're using the HTTP adapter to post a message

BizTalk Utilities - Frustration free BizTalk Adapters
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