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Magento with subdomain can not login after upgraded
I have a magento setup with sub domain in developing environment, after upgraded from 1.4.2 to 1.7.0, I can not login admin,
to people who ist want to know how to fix it,
I just changed config value web/cookie/cookie_domain from ‘.sub.domain.com’ to ‘sub.domain.com’, I deleted the fist dot
to people who want to know why it fixed the login
check the code in Mage_Core_Model_Session_Abstract::renewSession(), a sub domain starting with dot would fall in the second if and get cookie deleted after session regenerated