Users are always logged out on front end

Question

Users are always logged out on the front end on my Craft website. Even when logged in as admin I can access the CMS but on the front end user session always returns the following.

Craft\UserSessionService Object
(
    [_identity:Craft\UserSessionService:private] => 
    [_identityCookie:Craft\UserSessionService:private] => 
    [_userModel:Craft\UserSessionService:private] => 
    [_userRow:Craft\UserSessionService:private] => 
    [_sessionRestoredFromCookie:Craft\UserSessionService:private] => 
    [_dontExtendSession:Craft\UserSessionService:private] => 
    [allowAutoLogin] => 1
    [guestName] => Guest
    [loginUrl] => Array
        (
            [0] => /site/login
        )

    [identityCookie] => 
    [authTimeout] => 259200
    [absoluteAuthTimeout] => 
    [autoRenewCookie] => 1
    [autoUpdateFlash] => 1
    [loginRequiredAjaxResponse] => 
    [_keyPrefix:CWebUser:private] => 4e3924125ff89a395a13e8e5580209e2
    [_access:CWebUser:private] => Array
        (
        )

    [behaviors] => Array
        (
        )

    [_initialized:CApplicationComponent:private] => 1
    [_e:CComponent:private] => 
    [_m:CComponent:private] => 
)

Does anyone have any idea why this could be happening?

Answer 1

I tracked down a similar problem, and documented it here: The Case of the Missing PHP Session

I'm not sure if it'll address the issue you're having specifically, but it may give you some clue on where to look.