[TYPO3-english] IE8 loosing login session - in both FE and BE

[Sune Vestergaard]

We have some (not all) Internet Explorer 8 - which looses the session 
"shortly" after login to either FE og BE. I do not believe it is related to 
the "combatility-issue"!

After some investigation, it is quite clear that the session expires after 
the first Ajax call. If no Ajax call - no problem. You are able to log into 
e.g. the BackEnd of a new TYPO3 version 4.2. But after hitting some 
functionality using an Ajax call, you will on the next request find yourself 
no longer logged in. This could e.g. be the Clear Cache buttons. It seems 
likes it works - but on the next request you are no longer welcome :)
Many different (all?) TYPO3 versions seems affected. No problem observed in 
other version of IE (6,7) or FF or any other browser. Only some IE8 users is 
affected.

Same behavior in FE. Also with different types of Ajax implementations 
(libraries). It seems closely related to TYPO3 - since many other 
applications is with great success using Ajax.

The last really really puzzling observation in this regard - is that if I 
activate the "InPrivate-browsing" feature of IE8, everything seems to work 
perfectly.

In all situations - analyzing network traffic with makes me conclude that IE 
is accepting the fe_typo_user cookies that it is asked to use. After 
initially setting the cookie - all subsequent requests, including the coming 
Ajax request, has the new cookie value. Session will fail on the first Ajax 
Request. eID related ??

Any suggestions or solutions? Someone who can replicate this behavior?

Thank you in advance.

Best regards,
Sune Vestergaard