Ok... i have something that appears to be a DNN "FREAK" of Nature.
We totally had to rebuild an old DNN site from scratch. As a result, we have a number of old Tab ID pages that no longer exist. So to handle this i created a 404 error page which basically just says "The Page You Are Looking For Has Been Updated Or Moved" and set this in IIS...

HOWEVER i have an old page which says something like www.mydomain.com/Myinformation/tabid/... (NOTE: THIS PAGE WAS ON THE OLD SITE AND DOES NOT EXIST) now with the new site inplace... if a user had the above booked marked or clicked the OLD tabid from the old site... THEY ARE REDIRECTED TO OF ALL THINGS THE DNN CMS LOGIN SCREEN!

So here is what happens a user clicks on www.mydomain.com/Myinformation/tabid/... and then they are redirected on the NEW DNN SITE TO http://www.mynewwebsite.com/MyCustomL... (WHICH IS THE DNN LOGIN SCREEN!)

Note: the above urls were changed... but hopefully, you all get the picture of what i'm seeing

Any Ideas how to fix this? Should i try a 301 Redirect  .htaccess file? OR is this a "return url" redirect issue?
It is STRANGE that if someone has an old TAB ID booked marked to a page that nolonger exists that redirects to the LOGIN SCREEN?

Anyone... please advise on how to fix or a work-a-round ... PLEASE HURRY.
NOTE: THIS IS DNN 5.6.3

Thanks so much Steve for the info....

Your feedback reminded me to check to see where the new generated tab id was pointing too.... In my rush to fix this, it was over looked... but now that I slowed down to think about what you said, your information proved very helpful.

What was happening was this: The totally new DNN site had tabe IDs which DNN taged as Admin pages. So in the old DNN tab IDs, what users were trying to access were in fact pointing to Admin pages so DNN naturally redirected these users to our hidden login screen for DNN.

Some of these old tab IDs were even showing up on Google! and if you clicked the old tab IDs the user was taken to a locked down admin page and auto redirected to the DNN Admin login. (which of course confused people)

So i spent an extra hour or two generating A LOT of permanant page redirects in the new DNN Site until I can force Google to re-index the new site.

Again thank you for your feedback... in our rush to fix this, we overlooked the fact that the old tab IDs may have been going to different locked down Admin pages in the new DNN web site.

Thanks