Thank you Brains. I will learn a lot.

I am going to try my best with the help that you and Tim have provided me.

Below the output of ip a:

#ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether e4:e7:49:0a:e3:58 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.32/24 brd 192.168.0.255 scope global dynamic eno1
valid_lft 602500sec preferred_lft 602500sec
inet6 fe80::e6e7:49ff:fe0a:e358/64 scope link
valid_lft forever preferred_lft forever

Thanks Brains.

I will lear a lot.

Below the output

#ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether e4:e7:49:0a:e3:58 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.32/24 brd 192.168.0.255 scope global dynamic eno1
valid_lft 602500sec preferred_lft 602500sec
inet6 fe80::e6e7:49ff:fe0a:e358/64 scope link
valid_lft forever preferred_lft forever

Thank you again

So...
Your wireless device is not supported by the kernel you are running, perhaps you should try installing the driver from source by following method #1 in the link I provided, this is the best method as it would ensure the driver is compiled automatically if there is a kernel upgrade in the future.

Because the kernel from Debian backports did not support the wifi device, you may opt to uninstall it or just keep running with it. Because you are running Debian stable, it is highly unlikely there will be another kernel upgrade in the future as soon Debian testing (Buster) will be trasitioned to stable. I recommend you disable the Debian backports repo in your /etc/apt/sources.list file by putting a hash at the beginning of the line to avoid installing conflicting libraries from backports that could render your stable OS unstable (comment out backports sources).

1 members found this post helpful.

But...
Build the driver first before disabling backports repo, to ensure you use kernel headers for the kernel you choose to run with.

1 members found this post helpful.

Hi Brains. Thanks for your help. I tried the method 1 and the output in the prerequisete was:

#apt-get install linux-headers-`uname -r`
Reading list of packages ... Done
Creating dependency tree
Reading the status information ... Done
Do not can instal some pack. This may mean that
you asked for an impossible situation or, if you are using the distribution
unstable, that some necessary packages have not yet been created or are
They have taken out of «Incoming».
The following information can help resolve the situation:

The following packages have unfulfilled dependencies:
linux-headers-4.18.0-0.bpo.3-amd64 : Depende: linux-compiler-gcc-6-x86 (>= 4.14.17-1~) but 4.9.144-1 will be installed
E: Problems could not be corrected, you have retained broken packages.

Anyway I continued...

#apt-get install git build-essential dkms

Fine.

I continued...

# dkms install rtlwifi-new/0.6
Error! Your kernel headers for kernel 4.18.0-0.bpo.3-amd64 cannot be found.
Please install the linux-headers-4.18.0-0.bpo.3-amd64 package,
or use the --kernelsourcedir option to tell DKMS where it's located

#dkms install rtlwifi-new/0.6 --kernelsourcedir
Error! Your kernel headers for kernel 4.18.0-0.bpo.3-amd64 cannot be found.
Please install the linux-headers-4.18.0-0.bpo.3-amd64 package,
or use the --kernelsourcedir option to tell DKMS where it's located

It seems all this is about kaernel (Obvious right?)

I am going to do my research and I will let you know guys.

Thanks again!

Yes, this is the problem with using packages from repos not originally from Debian Stable, there will always be conflicts because of packages installed that are from Debian testing. Your best bet is to remove the back-ports kernel 4.18 and any dependencies that were installed with it, and disable the back-ports lines in /etc/apt/sources.list.

If you look at /var/log/apt/history.log, on the day you installed the kernel from back-ports you will see what all packages came with it.

Once you have you Debian Stable back to original configuration before installing the back-ports packages and are running the original kernel, you should have no issues with conflicting package versions. If you already removed the original kernel, you'll need to install it first and boot to that kernel before you can revert.

1 members found this post helpful.

If you already had back-ports line commented out in /etc/apt/sources.list when you did this, then there should be no issues, if back-ports was still enabled, you might need to remove this stuff also as some of it may be from Debian testing. ---> #apt-get remove git build-essential dkms

1 members found this post helpful.

Hi Brains. Thanks so much for your help. Now I have Wifi!

Best regards.