NOTE: This is not a duplicate of How to get my Intel Wireless 3165 to connect on 15.04?. That question dealt with a system (running 15.04, kernel 3.19) that did not connect via wireless at all (but presumably could connect via ethernet). The present issue deals with a system that can connect via wifi and ethernet, but the internet connection drops randomly on both wireless and wired (when either is used). In addition, both answers (which recommended upgrading to kernel 4.2) on that previous question cannot be applied to solve this issue. 16.04 already uses kernel 4.4 out of the box.
QUESTIONS: Why does the internet drop from wired and wireless even though they appear to remain connected? Where can I look to begin figuring this out? What diagnostics can I run to probe the wired issue?
SUMMARY: Internet drops 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 "The site can't be reached" screens in Chromium, or error messages when downloading/updating in Terminal, or stalled syncing in Insync application.
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 on a fresh install (yesterday) of Ubuntu 16.04 on a Dell Inspiron 15 5567 (dual boot). The issue also occurs when running on Live CD.
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.
This change from this post did not work:
sudo tee /etc/modprobe.d/iwlwifi-opt.conf <<< "options iwlwifi disable_11n=1"
This change did not work either:
sudo sed -i 's/wifi.powersave = 3/wifi.powersave = 2/' /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf
sudo lshw -class network *-network description: Wireless interface product: Wireless 3165 vendor: Intel Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: wlp2s0 version: 79 serial: 58:fb:84:55:21:52 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=4.4.0-62-generic firmware=17.352738.0 latency=0 link=no multicast=yes wireless=IEEE 802.11abg resources: irq:283 memory:df100000-df101fff *-network description: Ethernet interface product: RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:03:00.0 logical name: enp3s0 version: 07 serial: 18:db:f2:3c:d5:37 size: 100Mbit/s capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8106e-1_0.0.1 06/29/12 ip=192.168.1.13 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s resources: irq:279 ioport:d000(size=256) memory:df000000-df000fff memory:d0300000-d0303fff
lspci -knn | grep Net -A2 02:00.0 Network controller : Intel Corporation Wireless 3165 [8086:3165] (rev 79) Subsystem: Intel Corporation Wireless 3165 [8086:4410] Kernel driver in use: iwlwifi
Wireless info script pasted here.
I don't know what other diagnostics I can run for the wired connection.