Gfilui

A person who will transfer files to your machine will not be able to contact your machine. What is the first thing you want to check to find out what's wrong? How do you want to do it practically?

     To do this practically, I have to open the terminal in ubuntu, then I write:
I do this to check if the network connection is set up correctly
     $ ifconfig .
     $ nano / etc / network / interfaces
     Here you can change the network settings if something is set up incorrectly
     $ service network manager restart
     In some cases, a reboot will also work, as done
     $ reboot

Verfication

If I cannot ping the remote device I perform the following verification in this order (depend of the error message return by the ping) :

1. I ensure that my wifi is not "blocked" with the command rfkill list
   


2. I check the state of my network interfaces (UP) with the command ip link
   


3. I check my IP addresses with the command ip address
   


4. I check the route of my device with the command ip route
   


5. If i'm trying to reach an hostname I check my DNS configuration (nslookup)


6. I ping my default gateway


7. If I have reach this step is that I encouter a specific problem with the computer or the error is due to an network device

Solution

1. If the Wifi is "hard blocked" you can use the button on your keyboard to enable the Wifi or the command rfkill unblock all
   


2. A lot of reason can Down the state of an interface. Check your wire, if it is correcly plug in, .... Then use the command sudo ip link set [INT] up
   


3. There is a lot a possible reasons for a missconfiguration of an IP address.If an DHCP server is in your LAN you can use the command sudo dhclient -v [INT] to get a automatic configuration. If this doest not work you can manually configure an IP address with sudo ip addr add 192.168.1.1/24 dev [INT]
   


4. The DHCP server can configure the routes of your device (dhclient). If that does not work you can add it manually : sudo ip route add 10.10.10.0/24 via 192.16.1.254 dev [INT]
   


5. Check the file /etc/resolv.conf. Then try to get DNS configuration from your DHCP server (dhclient). This is not recommended to configure manually the DNS configuration.

For the step 6 and 7 you need a access to your gateway/network, so basically contact your administrator.

Note : The above commands are independant of NetworkManager and will work on other Linux systems than Ubuntu.

Sorry for my english. Hope this answer will help.