I've found another bug that is exactly as my issue, which is Bug 698302 (almost similar but different than this one), reported 3 years ago (!!!).
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/207456 Title: refuses to connect to localhost http server when in offline mode Status in The Mozilla Firefox Browser: Confirmed Status in Ubuntu: Invalid Status in “firefox” package in Ubuntu: Triaged Bug description: Binary package hint: firefox-3.0 system: Description: Ubuntu hardy (development branch) Release: 8.04 firefox: Installed: 3.0~b4+nobinonly-0ubuntu1 Candidate: 3.0~b4+nobinonly-0ubuntu1 Version table: *** 3.0~b4+nobinonly-0ubuntu1 0 500 http://au.archive.ubuntu.com hardy/main Packages 100 /var/lib/dpkg/status The computer in use is running an apache http server. It is not always connected to a network. The firefox home page is set to the localhost http server. When not connected to a network through either ethernet or wifi, starting firefox 3.0 results in a failure to connect to the local server. Manually changing to online mode rectifies the problem. This bug is specific to firefox 3, and did not occur in previous versions. To manage notifications about this bug go to: https://bugs.launchpad.net/firefox/+bug/207456/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
