Hello
thank you for the help!
I send several quires to the target site.
first I send the URL of the home page.
The ASP.NET sites usually have the VIEWSTATE parameter value in the HTML source of the home page or the main search page:
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUJLTk4NTIyOT...==" />

<input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEW.." />

I get the value of the VIEWSTATE and EVENTVALIDATION from the HTML source of the home page.
I use uri_escape() to substituted the signs / " with the right values (%2F,%3D etc.), and use these parameters to recreate the URL that the target site sends for a search.
The URL created looks something like this:
THE_HOST_NAME_URL?__EVENTTARGET=&__EVENTARGUMENT= __VIEWSTATE=#THE_VIEW_STATE_PARAMETER#&THE_SEARCH_PARAMETERS&__EVENTVALIDATION=#THE_EVENT_VALIDATION_PARAMETER#
I send this URL in a POST method,and instead of getting the results page, I get an error page:
HttpException (0x80004005): Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that &lt;machineKey&gt; configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) +160

When I take the same URL and paste it in the Mozilla FireFox window, (its being sent in a GET method) I get to the results page.
Any ideas on how to avoid the error page received when using the POST method?
Thank you,

In reply to Re^4: Validation of viewstate MAC failed by Anonymous Monk
in thread Validation of viewstate MAC failed by Anonymous Monk

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