[Typo3] cookie monster in IE

[Tim Harrison]

Greetings t3ers.  I think there's a cookie monster in my code, and I beg
your help tracking it down.  The first symptom is that fe user login is not
working for IE6, but works for firefox, on my typo3 3.7.0 site.  The hunt
led me to cookie management.  I can see that the fe_typo_user cookie is
being set appropriately in class.t3lib_userauth.php.  But the cookie does
not come back from an IE browser.  It does come back from firefox.  Here's
how I reproduce the problem:

1) log out of all sessions, delete all cookies, close all browsers
2) open browser, go to site home page
3) verify in logs that no cookie received and that SetCookie succeeded
4) hit reload on browser
5) check logs to see if cookie was received

For IE, no cookie received.  For Firefox plenty of cookie goodness.

Can anyone suggest how to track this down?  I suspect the problem is
somewhere in something I've done, since I have another typo3 site where this
does not occur (that is, the cookie returns from the IE browser).  The
working site has a completely different template, and different extensions
installed.

Thanks for your consideration,
-Tim Harrison (heedspin)