can't connect to outside world using openbox

[Francis Gerund <ranrund@gmail.com>]

Hello!

I have been running Debian 8 64-bit xfce.  Networking works fine.
Then I added openbox.  So now at the desktop manager screen I can
choose between xfce and openbox.  Networking still works fine using
xfce (network-manager).

But if I start up into openbox, or startup into xfce and then log out
and into openbox, although I can ping localhost, I can't seen to
connect to the outside world using Firefox.  (Which makes it hard to
fix the problem!).  But if I log out of openbox and back into xfce,
networking again is fine, and I can connect to the outside world.

So, how can I get openbox to communicate with the outside world?

Note: the openbox install was extremely minimal, the menu only added
Firefox and a terminal.  I manually added obconf, obmenu, and feh, per
the openbox article in the Debian wiki.