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yohbs
Asked: 2015-02-06 01:19:51 +0800 CST

Possible problem with wifi n standard

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Hia all,

I have recently upgraded my internet connection, which included changing the wifi router. Since then, my wifi connection is somewhat shaky, works great sometimes, sometimes completely dead (usually around midnight! very strange...), and these kinds of problems. Everything works great when I use a LAN cable or connect, connect via wifi to other networks, or connect to this network from other devices.

I suspect that the problem might be related to the fact that I might have disabled my 802.11n wifi. It was some time ago and I don't quite remember what I did (I asked this question). How would I check if I disabled the n standard, and how would I reverse it? Are there any other wifi diagnostic tools that might help me here?

Thanks

BTW, I'm running 12.04

EDIT:

Thanks for all the suggestions.

a) I don't have a iwlwifi.conf in /etc/modprobe.d. The result of ls /etc/modprobe.d is

alsa-base.conf               blacklist-watchdog.conf
blacklist-ath_pci.conf       dkms.conf
blacklist.conf               nvidia-304_hybrid.conf
blacklist-firewire.conf      nvidia-current_hybrid.conf
blacklist-framebuffer.conf   nvidia-graphics-drivers.conf
blacklist-modem.conf         oss-compat.conf
blacklist-oss.conf           vmwgfx-fbdev.conf
blacklist-rare-network.conf

b) The result of lspci -nn | grep 0280 is

03:00.0 Network controller [0280]: Intel Corporation Centrino Wireless-N 2230 [8086:0887] (rev c4)
12.04

2 Answers

  1. The first place I would look for parameters like those in the other post would be cat /etc/modprobe.d/iwlwifi.conf and then check what parameters you can use with modinfo -p iwlwifi If you find that the cat command shows just options iwlwifi 11n_disable=1 you can delete the file sudo rm /etc/modprobe.d/iwlwifi.conf and reboot

    EDIT: Please add the result of cat /etc/modprobe.d/iwlwifi.conf to your question before using sudo rm /etc/modprobe/iwlwifi.conf

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  2. First, check the settings in the router. WPA2-AES is preferred; not any WPA and WPA2 mixed mode and certainly not TKIP. Second, if your router is capable of N speeds, I have better luck with a channel width of 20 MHz in the 2.4 GHz band instead of automatic 20/40 MHz. I also have better luck with a fixed channel, either 1, 6 or 11, rather than automatic channel selection. Also, be certain the router is not set to use N speeds only; auto B, G and N is preferred. After making these changes, reboot the router.

    Next, I recommend that your regulatory domain be set explicitly. Check yours:

    sudo iw reg get

    If you get 00, that is a one-size-maybe-fits-all setting. Find yours here: http://en.wikipedia.org/wiki/ISO_3166-1_alpha-2 Then set it temporarily:

    sudo iw reg set IS

    Of course, substitute your country code if not Iceland. Set it permanently:

    gksudo gedit /etc/default/crda

    Use nano or kate or leafpad if you don't have the text editor gedit.

    Change the last line to read:

    REGDOMAIN=IS

    Proofread carefully, save and close the text editor.

    Next, I'd set IPv6 to Ignore in Network Manager: http://docs.fedoraproject.org/en-US/Fedora/18/html/Installation_Guide/images/netconfig/network-connections-ipv6-ignore.png This example is for ethernet, but you want wireless.

    If these changes do not help, please try:

    sudo -i
echo "options iwlwifi 11n_disable=8"  >  /etc/modprobe.d/iwlwifi.conf
exit

    Reboot and test.

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