Xubuntu. No network with Intel I219-V ethernet card

xubuntu 16.04 does not recognize Intel I219-V Ethernet card.
solution is to download driver sources from Intel Downloads Site then unpack sources to your home catalog. Find file nvm.c file and open it in editor.
Find function e1000e_validate_nvm_checksum_generic(struct e1000_hw *hw) and comment body as shown:

s32 e1000e_validate_nvm_checksum_generic(struct e1000_hw *hw)
{

    /*
s32 ret_val;
u16 checksum = 0;
u16 i, nvm_data;

for (i = 0; i < (NVM_CHECKSUM_REG + 1); i++)

{
    ret_val = e1000_read_nvm(hw, i, 1, &nvm_data);

   if (ret_val)

  {
    e_dbg("NVM Read Error\n");
    return ret_val;
   }
checksum += nvm_data;
}

if (checksum != (u16)NVM_SUM) {
  e_dbg("NVM Checksum Invalid\n");
  return -E1000_ERR_NVM;
}

    */
return 0;

}

after that, build and install new module:

make

sudo rmmod e1000e
sudo make install
sudo modprobe e1000e

after that Ethernet should work.

This fix found on: https://unix.stackexchange.com/a/295052/23506 

Ubuntu. Cannot upgrade because of full /boot partition. Freeing some space

If you try to upgrade linux distribution (for example from 14.04 to 16.04) sometimes upgrade fail because of no free space at /boot partition. This happens because there are old kernel installed that are no longer needed. To remove old kernel you shoul issue command like this:

sudo apt-get purge linux-image-x.x.x-xx-generic

where "x" are numbers. so you remove all kernels except one that is used. ( check it with uname -r command). Usually in /boot partition there are many of kernels, so removing them one by one is time consuming operation. To make it more convenient use that crazy long command and wait :)

sudo apt-get purge $(dpkg -l linux-{image,headers}-"[0-9]*" | awk '/ii/{print $2}' | grep -ve "$(uname -r | sed -r 's/-[a-z]+//')")

 It remove all unused kernels from your /boot partition.

Xubuntu 14.04 how to enable remote access.

1. Install vino vnc server:

sudo apt-get install vino-server

2. run vino preferences:

suod vino-preferences

3. configure preferences:

4. Update the firewall:

sudo ufw allow from any to any port 5600

5. Update the encryption requirements for remote access:

sudo apt-get install dconf-editor

dconf-editor

6. Disable require encryption:

7. Update the session manager via enabling Settings->Session and startup->Application autostart->Desktop Sharing:

8. Restart computer and try to connect vith any vnc client.

How to grant root privileges in ubuntu for existing user

You need to add user to the "sudo" group. If you already created user "test" add user to the "sudo" group by issuing this command in terminal:

sudo usermod -a -G sudo test

check that ssh daemon is running:

sudo service ssh status

if firewall activated, add rule to allow ssh:

sudo ufw allow ssh