The password that broke the internet. Part 1: CentOS vs Asus

Alarm! Everything written below is the result of my thoughts before I got to the real essence of the problem.

I wanted to set up my own "dropbox" with blackjack and all the trimmings. Bought $200 worth of hardware for a server, installed CentOS 7 with Qemu/KVM, configured bridge and port forwarding on the router. Installed Nextcloud on the virtual machine and waited for happiness. But not only did happiness not come, it also started breaking the internet in the network every 2 minutes.

After two days of divination with coffee grounds, it turned out that the internet only drops if this wonderful server is plugged into the network. Unpleasant. After another two days of divination with stronger drinks, reconfiguring everything and everyone, including replacing the network card, disabling everything that could and couldn't be disabled on the router, reflashing the latter, etc., I came to the conclusion that black magic and Obama's agents were to blame for everything. But being a staunch fighter, I decided to check the same computer but running under Fedora 25 Live. And lo and behold, it worked and got along with the router like Monterey Jack with cheese.

In general, without ever finding out what the real cause was, through experimental means I arrived at a working state by simply installing the latest stable kernel on CentOS. And now, how to do it:

Import the gpg keys of the repository with fresh kernels
sudo rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

Connect the repository itself (this one is for CentOS 7)
sudo rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm

To choose a repository closer
sudo yum install yum-plugin-fastestmirror

Install the fresh kernel
sudo yum --enablerepo=elrepo-kernel install kernel-ml

Reboot. Check.

p.s. installing a new kernel doesn't set it in grub to load by default, so you can additionally do the following:

Look with your eye, at what number our new kernel is here /etc/grub2.cfg. In theory, it should be the very first, which means zero.

If everything worked after reboot, make it default.
sudo grub2-set-default 0

p.s.s. everything written above is complete nonsense. I hope you didn't repeat this at home.

To be continued...