[SOLVED] [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Issues related to configuring your network
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CorentinBL
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[SOLVED] [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby CorentinBL » 2017/12/30 09:58:24

Hello everyone,

I am very new to Linux and for the purpose of my PhD, I have to use CentOS. I have a Dell Precision 5520 laptop computer which was shipped with Ubuntu 16.04 LTS. Last Wednesday, I downloaded CentOS 6.9 from the official source (https://wiki.centos.org/Download), mounted the DVD1ISO file on a USB key with Rufus 2.18 and the installation went correctly. However, I still have a bunch of problems, the most important one being that I can't see any Wi-Fi hotspots and I can't connect to them.

First, I did some research to understand which network controller do I have. lspci returns "Intel Corporation Wireless 8265 / 8275 (rev 78)". I checked on the dedicated Intel website (https://www.intel.com/content/www/us/en ... rking.html) and downloaded the corresponding archive "iwlwifi-8265-ucode-22.361476.0.tgz". As it's said, I copied the .ucode file in the /lib/firmware folder. However, it didn't change anything after reboot.

With some further research, I discovered that I depends on the kernel versions. uname -r returns "2.6.32-696.16.1.el6.x86_64", which is before the 4.6 kernel recommended for the Intel driver. So I'm basically stuck here.

From what I understand, my hardware is "too recent" for my software, is that correct? But in that case, how can I get Wi-Fi to work? I have no Ethernet port so right now, the temporary solution that I use is my smartphone as a USB-hotspot.

Among the ideas that I have, the first was to upgrade the kernel while still using CentOS 6.9, but I don't know if it's possible and how. CentOS 6.9 is a requirement for my PhD, so I can't install CentOS 7.4. I have also read about The Backport Project (https://backports.wiki.kernel.org/index.php/Main_Page) but I am not sure that this is a solution.

I would be very grateful to anyone who has thoughts or solutions to suggest, and I can provide further information regarding my hard- and software if needed.

Thank you in advance,

Corentin.
Last edited by CorentinBL on 2018/01/05 14:20:38, edited 1 time in total.
French PhD Student - CentOS user since Dec. 27th 2017

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TrevorH
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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby TrevorH » 2017/12/30 11:57:11

Is there a reason for picking CentOS 6 rather than 7? Both are now quite old - CentOS 7 came out more than 3 years ago, CentOS 6 originally came out in 2010 but if you `yum update` regularly then you'll still get security updates for it. However CentOS 7 has much more support for newer hardware and I'm pretty sure your card would be supported out of the box.

I don't think your card is supported by the CentOS 6 kernel. To confirm this, run

grep -i 8086 /lib/modules/$(uname -r)/modules.* | grep -i 08b1

(only substitute the values you see from lspci -nn | grep -i wire - here with a 7265 I see "01:00.0 Network controller [0280]: Intel Corporation Wireless 7260 [8086:08b1] (rev 73)" so use the 8086:xxxx numbers from those commands not the 8086:08b1 that I've used).
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pjsr2
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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby pjsr2 » 2017/12/30 18:12:19

I recently had a similar experience with this network card when installing CentOS 7.4. Even the latest standard kernel in CentOS 7.4 did not yet handle this network card on my new laptop. I installed kernel-ml-4.14, following instructions from http://elrepo.org/tiki/kernel-ml. With that kernel the network card is working properly. You could try the same with your CentOS 6.9 installation.

Note that after installing kernel-ml, it does not automatically become your default kernel. You will have to adjust your grub config file manually to make it the default kernel.

Unless your PhD is in history, I do not understand why your university insists on CentOS 6.9. CentOS 6.x is showing its age, especially in multimedia and web-oriented applications. Since you are starting something new, you really should consider to go for CentOS 7.

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CorentinBL
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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby CorentinBL » 2018/01/03 09:35:20

Sorry for my late reply, and best wishes for 2018 to all.

@all: My PhD is a cooperation between a lab and a company that operates worldwide. I will work on finite element simulations so I have to comply with the company's rules in terms of OS and software versions because my work might be reused later. I understand your points of view and I also wish I could use the latests versions, but I have unfortunately no room for maneuver.

@TrevorH: The fact that my card was not supported either was also my guess. Regarding the commands you suggested, "lspci -nn | grep -i wire" returns "01:00.0 Network controller [0280]: Intel Corporation Wireless 8265 / 8275 [8086:24fd] (rev 78)" so I used 24fd in the next command. And "grep -i 8086 /lib/modules/$(uname -r)/modules.* | grep -i 24fd" returns indeed nothing.

@pjsr2: This idea is interesting, thank you! The installation was successful, can you tell me more about how to adjust the grub config file? And is this reversible? By that I mean that if kernel-ml doesn't change anything, can I go back to the original kernel?

Thank you a lot for you help!

Corentin.
French PhD Student - CentOS user since Dec. 27th 2017

pjsr2
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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby pjsr2 » 2018/01/03 10:57:04

http://ask.xmodulo.com/change-default-boot-kernel-centos.html describes how you can set the default kernel to boot.

As long as you do not uninstall any of the existing kernels, you can always revert to an older kernel by selecting it from the boot menu. (And if you have uninstalled an old kernel, you can always install it again.)

Support for newer hardware may or may not be back-ported to the CentOS kernel in the 6.10 release. See the update policy described in https://access.redhat.com/support/policy/updates/errata. You could try to install a new CentOS kernel again once 6.10 is released. Until then you should stick to the kernel-ml kernel. It is advisable to update kernel-ml as needed to ensure you are not running a kernel with known security issues.

If you want to prevent automatic updates of the CentOS kernel, you can add a line

Code: Select all

exclude=kernel*

in the [updates] section of the file /etc/yum.repos.d/CentOS-Base.repo

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CorentinBL
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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby CorentinBL » 2018/01/04 08:21:34

Thank you for the link. When I open the /boot/grub/grub.conf file, I see now 3 items :

    CentOS (4.14.11-1.el6.elrepo.x86_64)
    CentOS (2.6.32-696.16.1.el6.x86_64)
    CentOS 6 (2.6.32-696.el6.x86_64)

The default boot value was 1, which means that the system boots using CentOS (2.6.32-696.16.1.el6.x86_64). I changed it to 0 to boot using CentOS (4.14.11-1.el6.elrepo.x86_64). However, I was blocked when I rebooted as you can see with the picture attached.

Right now I changed the default value back to 1, and I will also try to see what happens when I choose 2.
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French PhD Student - CentOS user since Dec. 27th 2017

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TrevorH
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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby TrevorH » 2018/01/04 08:34:35

Those are not errors to be concerned about. Remove rhgb quiet from the kernel command line for that kernel and try it again. It won't fix the issue but you'll see more info about what went wrong.
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CorentinBL
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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby CorentinBL » 2018/01/04 09:31:50

Thank you, I just did it. The boot stops right after "certmonger" has been started. I can see the green "OK" next to it but then nothing happens. It looks like this thread: viewtopic.php?t=3119
French PhD Student - CentOS user since Dec. 27th 2017

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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby TrevorH » 2018/01/04 10:14:53

Installed proprietary video drivers from nvidia/ATI/virtualbox/vmware? If you did so using the manufacturer's download then you probably need to reinstall them each and every time you update the kernel. When using the CentOS supplied kernel you can use the ELRepo provided kmod-nvidia packages which work across kernel updates (most of the time) but for the ELRepo kernel you have to reinstall the drivers all the time.
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Re: [CentOS 6.9] Can't see and connect to Wi-Fi hotspots

Postby CorentinBL » 2018/01/04 10:53:17

I haven't installed any proprietary drivers from these companies. I think the cause of the problem is different from the thread, but the outcome is the same, that's what I meant.
French PhD Student - CentOS user since Dec. 27th 2017