Day: April 14, 2016

Network Manager shows eth0 and wlan0 unmanaged

After starting the OS, there is no internet connectivity. The network manager shows that eth0 and wlan0 are not managed.

Make sure that the eth0 and wlan0 are discovered. Run the following command.

ifconfig -a

If the ethernet and wlan can be seen in the output but no ip address is allocated to it, check if the dns nameserver exists.

sudo gedit /etc/resolv.conf

If this list is empty then add the following entries in it.

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 8.8.8.8
nameserver 8.8.4.4

These point to the Google DNS.

Try to ping any website. Example:-

ping www.google.com

If the result is successful we have a working conncetion.

If ping fails, then the system doesn’t manage the network drivers.

For the system to manage the network devices, we have to make changes in the /etc/NetworkManager/NetworkManager.conf file

sudo gedit /etc/NetworkManager/NetworkManager.conf file

The displayed output will be in the format:-

[main]
plugins=ifupdown,keyfile,ofono
dns=dnsmasq

no-auto-default=XX:XX:XX:XX:XX:XX,

[ifupdown]
managed=false

Change the managed value from false to true

[main]
plugins=ifupdown,keyfile,ofono
dns=dnsmasq

no-auto-default=XX:XX:XX:XX:XX:XX,

[ifupdown]
managed=true

Restart the network service

sudo service networking restart.

Boot Delay due to Wait for Network Configuration

This problem happens sometimes when ubuntu starts up. You can’t really boot to the interface sometimes.

Splash Screen with the 5 dots and a message saying:

waiting for network configuration

followed by:

waiting an additional 60 seconds for network configuration

Solution to this problem is following :

In /etc/network/interfaces this changes all interfaces (except lo) from auto to allow-hotplug. This way the boot is no more waiting for the interfaces to come up first.Example before (look at auto eth0):

auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp

auto wlan0
iface wlan0 inet dhcp

Example after (look at allow-hotplug eth0):

auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
iface eth0 inet dhcp

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp

 

Install Build-Essential

Informational list of build-essential packages

Other Packages Related to build-essential

  • dpkg-dev (>= 1.17.11)
    Debian package development tools
  • g++ (>= 4:5.2)
    GNU C++ compiler
  • gcc (>= 4:5.2)
    GNU C compiler
  • libc6-dev
    GNU C Library: Development Libraries and Header Files
    or libc-dev
    virtual package provided by libc6-dev
  • make
    utility for directing compilation
    also a virtual package provided by make-guile
    To Install the build-essential package:
    sudo apt-get update
sudo apt-get install build-essential