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Since the update to 15.04, my dual-boot Dell XPS can't use my Wifi network. It can't even update itself now. Network is fine when I boot to Windows.

When I reboot to Ubuntu, I can see both of my two my Wifi networks connect, the signal looks fine (as it does in Windows) but I can't ping anything and the Firefox browser can't get to anything.

When I reboot back to Windows, everything is fine.

In writing this, I see several similar questions to the right side of the screen, so I will look at these to see if any of them address the issue here.

TIA to any who have seen this issue and know how to fix it. Worst case, I suppose I can save my data files from the Ubuntu partition and then reinstall 15.04 (or 14.10) from scratch.

Update 2015-05-29 I just ran the following command:

mike@Old:~$ lspci -knn | grep Net -A2

03:00.0 Network controller [0280]: Intel Corporation Centrino Advanced-N 6230 [Rainbow Peak] [8086:0091] (rev 34)

Subsystem: Intel Corporation Centrino Advanced-N 6230 AGN [8086:5221]
    Kernel driver in use: iwlwifi
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  • Please edit your post and add output of lcpci -knn | grep Net -A2 terminal command there.
    – Pilot6
    May 28, 2015 at 13:59
  • Pilot6, I have added the information requested. I'm now on a wired connection and am considering updating the 15.04 software, but will wait until I hear back. Thanks! May 29, 2015 at 16:08

2 Answers 2

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I've encountered the same problem with Ubuntu MATE 15.04 on my Dell XPS M1730 with an internal Intel PRO/Wireless 4965 wifi adapter. It couldn't even maintain a connection in the installer ISO, which results in a rather broken OS install.

My wifi adapter works fine in Linux Mint Debian Edition with the iwl4965 driver, and even better in Windows 7. It has also worked fine in Ubuntu versions prior to 15.04 (including 14.04 LTS and 14.10), so there's likely a regression somewhere.

Anyways, here's a possible solution that I may try today: Connect the laptop to the Internet via an Ethernet cable, reinstall Ubuntu 15.04, then do a post-install package upgrade pass. If the bug has been found and fixed since they made the 15.04 installers, this could result in a working system.

Update: This didn't work for me. I also tried messing with modprobe configuration for the iwlwifi/iwlegacy/iwl4965 modules and it didn't help. Hopefully someone will fix this issue by the time 15.10 rolls around.

Update 2: I also tried switching out Network Manager for WICD and a bunch of other common things like tweaking modprobe options, but that didn't help either. I suspect the problem (at least for me) may be that the Linux Intel wifi drivers don't like some settings on the router/AP side, even though the Windows drivers work fine.

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I think I may have solved my own issue by changing some settings on my Tomato-based router.

In particular, I set the following settings disabled to help with connection stability: Afterburner, CTS Protection Mode, Bluetooth Coexistence, Frame Burst, Overlapping BSS Coexistence, No Ack (WMM), APSD (WMM).

I also made sure to use the following on 5ghz: 40mhz channel width, auto channel, WMM Enabled (needed for >54mbps on my Intel 4965 mini-PCIe wifi card).

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  • FWIW, I just booted from a 15.04 DVD. The network connection was successful and I'm able to browse anywhere. The 15.04 upgrade to HD, on the other hand, still fails. I'll try to refresh from a wired connection, and if that doesn't do the trick then I'll have to re-install over the existing installation. Bummer ... Ben, I'll check my router settings and see how they match yours. This might help with intermittent 5gHz issues with my tablet connection. Jun 2, 2015 at 3:07

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