This is not a duplicate of bug 911706: that is about being connected to the Internet without using Network Manager. But you shouldn't need to be connected to the Internet *at all* to install a local .deb file (unless it has uncached dependencies). Bug 1014277 is the equivalent case for packages in a local repository.
This is not a duplicate of bug 911706: that is about being connected to the Internet without using Network Manager. But you shouldn't need to be connected to the Internet *at all* to install a local .deb file (unless it has uncached dependencies). Bug 1014277 is the equivalent case for packages in a local repository.