[TYPO3-english] Multiple login issues when login box on home/root page

[Jure Dejanovic]

Hi all and an happy new year ;-)

Some help needed here as I'm stuck now without any idea on how to fix 
this... after several days of work.

Here's the story:
As far as there is no login box on the home/root page of my website, 
there are no problems. All login boxes on sub-pages are working fine.

But as soon as I put a login box on the home/root page, none are working 
anymore depending on the browser and/or computer.

I'm using fe_login, but I know that the authentication process is a core 
feature.

For example:
- I'm unable to login through chrome except when I do some 
manipulations: Erasing session cookies, refreshing the page and logging. 
This trick is not working on my customer browser/machine.
- I have no problem to login through IE9 but my customer do and a lot of 
his customers too.
- Sometimes, I can't login through the home/root page of firefox, 
whatever I do. To be able to login again, I have to use the sub-page 
login box, when done, then I can login via the home/root page again.

Some remarks:
- First user's login seems to be always ok. But after the first login, 
problems mentioned here above are appearing.
- This issue was not present on my test server. It appeared on the 
production one. Migrating back the production site to the test server 
didn't solve the issue.
- I set the permalogin, but with all this issues, I removed it. But 
didn't solve the issue neither.
- I tried to set those parameters to multiple values
$TYPO3_CONF_VARS['FE']['lockIP'] = '0';
$TYPO3_CONF_VARS['FE']['lifetime'] = '464'; // Modified or inserted by 
TYPO3 Install Tool.
$TYPO3_CONF_VARS['FE']['sessionDataLifetime'] = '31536000'; // Modified 
or inserted by TYPO3 Install Tool.
$TYPO3_CONF_VARS['FE']['permalogin'] = '1';
$TYPO3_CONF_VARS['FE']['maxSessionDataSize'] = '100000'; // Modified or 
inserted by TYPO3 Install Tool.
But no hope...

I guess that it is a cookie issue but I don't know in which way as there 
are such a variety of behavior... depending on machines, browser and 
user's history.
I did a lot of research on google, maybe in a wrong way as I didn't 
found anything to help me much further. I just found some traces that 
others had the same issue, but very few: 
http://old.nabble.com/Re%3A-tx_felogin_pi1-on-every-page-not-working-as-typoscriptObjectPath-p34491732.html

If someone could help, or at least give me a clue where to search, I'll 
be very grateful as this issue is driving me mad.

None the less, I wish all of you a happy new year,

Jure