We're currently working with a Magento (v 220.127.116.11) cached by Varnish (v 3.0.5). The varnish control is done by Turpentine (v 0.6.8).
When a user has no cookies for the site he has to login twice to get to the
customer-account-index and get logged in. After the first login the user gets redirected to a blank login page without errors. At the same time the
frontend_cid cookies are created. The
persistent_shopping_cart) cookie is not created and the user is not logged in.
The automatically login after the registration process is working fine. When the user already has the
frontend_cid cookies he can log in on first try.
After the second login the user gets logged in and all cookies are set correctly.
The cookie domain is left blanc. The input
name="form_key" is set within
Would like to see all users beeing logged in after the first time they enter their credentials correctly. But that does not work when user browses in private mode or visits the page for the first time (registering earlier on another computer).