[TYPO3-dev] Loin Problems with Internet Explorer. Searching for starting points..

[Sebastian Gebhard]

Hi *,

I've got a problem with a Website running on TYPO3 4.1.13.
Automated logouts were reported from Frontend-Users.

A little investigation suggests that Users of all Internet Explorer Versions (probably only on 
Vista) are affected. When you log into the FE with IE it tells you your login was successful but on 
the next page/action you're immediatelly logged out.

BE works fine with IE.

As far as I can tell it's NOT because of the compatibility mode, because the problem shows up at 
_all_ IE versions, manually trigger compatibility mode in IE8 did not solve the problem and <meta 
http-equiv="X-UA-Compatible" content="IE=8" /> did not help.

I'm rather sure that some time ago login worked in IE, but can not say how long this problem exists 
yet or what was changed that could have caused the problem.

My question is what starting points do you suggest, that I could investigate?

Kind regards and thanks in advance,
Sebastian Gebhard