VirtualBox www connection problems

Sometimes the connection is gone for downloading new apps. Then you have to check the ips, supposed you have everything ok in VirtualBox network settings.
First you can check your IP with 

 $ sudo ifconfig

This will give a output something like this 

eth0      Link encap:Ethernet  HWaddr d4:9a:20:09:41:14  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:44 Base address:0xe000 

eth1      Link encap:Ethernet  HWaddr 00:26:bb:1b:e5:e4  
          inet addr:xxxx.xxx.xxx.xxx  Bcast:xxx.xxx.xxx  Mask:255.255.255.0
          inet6 addr: fe80::226:bbff:fe1b:e5e4/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:119971 errors:1 dropped:0 overruns:0 frame:657943
          TX packets:112631 errors:44 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:65076102 (65.0 MB)  TX bytes:18417850 (18.4 MB)
          Interrupt:23 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:29612 errors:0 dropped:0 overruns:0 frame:0
          TX packets:29612 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:7134579 (7.1 MB)  TX bytes:7134579 (7.1 MB)
 

Maybe even more at your terminal but... Also i have masked my IP the router has given me, for the tutorial and security reasons, this line 

          inet addr:xxxx.xxx.xxx.xxx  Bcast:xxx.xxx.xxx  Mask:255.255.255.0

Now we know the network eth0 is down and can fix this with first add do

 $ sudo ifconfig eth0 down
 $ sudo ifconfig eth0 up 
 $ sudo dhclient eth0