I have been working to resolve this redirect loop on a site I've been attempting to port for months with the support of Evotiva, though have not discovered the source of the problem. I have researched this, reviewed the code, submitted posts on this forum and made efforts to follow each suggestion I have found with out any resolution. I am at the stage where I'm considering hiring someone with advanced knowledge of installation issues since I have not gotten any replies from such in this forum.

Below I'll summarize what I've done to date and what references I've used with one last apeal to any who may have insights to how to resolve this problem in this community. Please consider this thread summarizing my efforts to address the rediredt loop and offer advice if you have clear recommendations of what might resolve this.
Thanks,
King

I'm attempting to port a DNN site from one ISP to another and purchased Evotiva's BackupScript module to facilitate the move. I had a fresh install on the destination host that was working and removed it to then restored a backup of the current live site (database & site files) that is hosted on another ISP's server. Both setups had DNN 4.09.00 running on them.

Once I ran the restore on the destination server, the site began a redirect loop when landing on the site page (the page keeps trying to redirect until Firefox tells you it has stopped trying). I've found a few resources and tried several things short of the ISP restarting IIS with no success in overcoming this problem. Here are the references I've found:

http://www.bestwebsites.co.nz/dotnetnuke/solving-the-dotnetnuke-redirect-loop/
http://weblogs.asp.net/christoc/archive/2008/06/19/dotnetnuke-homepage-won-t-load-keeps-redirecting.aspx
http://www.codeproject.com/KB/aspnet/fix_dnn_redirect_loop.aspx
http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/107/threadid/271043/scope/posts/Default.aspx
http://www.programmersanonymous.net/content/NETTutorials/tabid/55/EntryID/1/Default.aspx
http://blogs.snapsis.com/PermaLink,guid,87c379cc-c700-4eb8-a48d-e778aeef65fa.aspx

Here are some things I've tried:

•     I queried and updated the PortalAlias table to have the URL for the new host (no trailing slash), then redirect loop started
•     I cleared my cache and closed/opened browser to eliminate any possible issues with the browser
•     Since I couldn't restart IIS, I tried to force an “application pool” restart by editing/saving the web.config then uploading & then renaming it to cause an application error then changing the name back but this did not resolve the issue.
•     I tried to enable the 3.5 framework to fix this but the host provider option is just to enable 1.1 or 2.0/3.0/3.5 and seems to suggest it is installed.
•     I inserted a HostSetting record to disable AJAX: INSERT INTO HostSettings (SettingName, SettingValue, SettingIsSecure) VALUES ('EnableAJAX', 'N', 0);
•     I updated all the references in the web.config and replace every Version=1.0.61025.0 with Version=3.5.0.0, but could not restart IIS
•     I tried changing the Trust setting to FULL rather than the designed MEDIUM in the web.config (even though the ISP may have different permissions)
•     I tried uncommenting the usePortNumber="true" in the web.config

I checked with the current ISP and destination ISP to confirm what trust level that they allow the sites on their shared servers. They both use MEDIUM trust and neither suggested they had modified the permisions from the default medium trust settings.

The DNN site that was setup initially on the destination site was working with the AJAX controls. We initially suspected it is related to AJAX but disabling it with the HostSettings table and changing web.config version references did not help. I studied the various redirect mechanisms in the DNN code to make sure I understand them but I'm missing something.

I've resorted to deleting the database and creating an "empty" database several times to "start fresh". I also deleted all the site contents and re-uploaded all the DNN site files just to have a clean starting point. I have successfully restored of the site database and site files using the Evotiva backup module, but the redirect loop has returned.

The last Q/A in this post below says to add the Portal Alias before loading the page for the first time to prevent a redirect loop due to caching. After several reinstallation's of the entire site and updating the PortalAlias table prior to loading a page still results in the redirect :
 
http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/107/threadid/105609/scope/posts/Default.aspx

I've edited the web.config to trigger a recompile, but we are not able to actually cause an IIS restart (unless I were to cause five severe errors that would cause IIS to restart) since the ISP would not restart IIS.

Hi!

I got the exact same error on my fresh vista installation.

Here is what i did in order to get it to work:
While debugging if found that the redirect comes from file "PageBase.vb" (Line 530). The comment above the line says "suppress AJAX error in Medium Trust", but it actual prevents the error page from showing redirecting you to the page you came from.

Set a break point there and inspect the "objBasePortalException.Message" for the error you got.
Mine was:

System.Security.SecurityException: Request for ConfigurationPermission failed while attempting to access configuration section 'system.web/deployment'. To allow all callers to access the data for this section, set section attribute 'requirePermission' equal 'false' in the configuration file where this section is declared. ---> System.Security.SecurityException: Request for the permission of type 'System.Configuration.ConfigurationPermission, System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' failed.
at System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet)
at System.Security.CodeAccessPermission.Demand()
at System.Configuration.BaseConfigurationRecord.CheckPermissionAllowed(String configKey, Boolean requirePermission, Boolean isTrustedWithoutAptca)
The action that failed was:
Demand

So i edited the file "C:\windows\Microsoft.NET\Framework\v2.0.50727\CONFIG\web.config" and added the value requirePermission="false" to the section "compilation" and "deployment".

Thats it - everything's OK  for me now.
Hope that helpes you too!

Cheers
Guenther