Repeated Internet Failure on Dell Inspiron 5567

Internet drops randomly every 1-30 minutes when connected via wired or wireless (i.e., this is a problem on both wired and wireless) even though connection icon indicates the computer is still connected.

Disconnecting and reconnecting via the connection icon resets internet temporarily until the next random drop.

Dropped internet is discovered with "This site can't be reached" screens in Chromium, or error messages when downloading/updating in Terminal, etc.

Internet drops more frequently on wireless than on wired.

It seems to disconnect more frequently with heavier internet use (e.g., downloading multiple files, opening several webpages in quick succession).

This is a fresh install of Ubuntu 16.04 on a Dell Inspiron 15 5567 (dual boot).

Ethernet and WiFi both work without disconnecting in Windows 10 on the same machine, and ethernet and wifi work on other machines running Ubuntu and Windows with the same router, so it is not a hardware or router issue.

Additional info posted here:
http://askubuntu.com/questions/885626/why-does-internet-suddenly-fail-on-both-wired-and-wireless-connections-ubuntu-1