Apt-Get Update: failure to fetch; can't connect to any sources

the first sample methode to resolve apt-get update errors is to add an alternate DNS servers (the public DNS servers run by Google) by putting this lines  to your /etc/resolv.conf(tested on ubuntu)



 nameserver 8.8.8.8 

also there is another  method that is the best way I have found since I run server edition and have no GUI tools! Below I will show you how :

Actually for me it made this easier by putting all into the /etc/network/interfaces file. The same configurations that you would have written to resolv.conf can now be in the same file as your network adapter configurations like the example below:

 # The loopback network interface  
 auto lo  
 iface lo inet loopback  
 # The primary network interface  
 auto eth0  
 iface eth0 inet static  
     address 192.168.1.2  
     netmask 255.255.255.0  
     network 192.168.0.0  
     broadcast 192.168.1.255  
     gateway 192.168.1.1  
     dns-nameservers 8.8.8.8  
     dns-search local  

that all !! Hope it Helps SomeOne :)