ifconfig eth0 up/down

[Thufir]

I was moving some stuff about and disconnected the cable modem, then 
booted the pc.  I reconnected the wires, ensured that all the lights on 
the were solid, with the activity light blinking on the modem and network 
card.  However, I was unable to ping google or connect out.  Here's what 
I had:

thufir at ARRAKIS:~$ 
thufir at ARRAKIS:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:16:ec:23:af:88  
          inet addr:70.71.111.41  Bcast:70.71.111.255  Mask:255.255.252.0
          inet6 addr: fe80::216:ecff:fe23:af88/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:25857 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1064 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:3193566 (3.1 MB)  TX bytes:107387 (107.3 KB)
          Interrupt:19 Base address:0xb000 

eth1      Link encap:Ethernet  HWaddr 00:0d:88:37:fa:22  
          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:17 Base address:0xc800 

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:22 errors:0 dropped:0 overruns:0 frame:0
          TX packets:22 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1220 (1.2 KB)  TX bytes:1220 (1.2 KB)

thufir at ARRAKIS:~$ 
thufir at ARRAKIS:~$ sudo ifconfig eth0 down
thufir at ARRAKIS:~$ sudo ifconfig eth1 down
thufir at ARRAKIS:~$ 
thufir at ARRAKIS:~$ sudo ifconfig eth0 up
thufir at ARRAKIS:~$ sudo ifconfig eth1 up
thufir at ARRAKIS:~$ 
thufir at ARRAKIS:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:16:ec:23:af:88  
          inet addr:70.71.111.41  Bcast:70.71.111.255  Mask:255.255.252.0
          inet6 addr: fe80::216:ecff:fe23:af88/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:26606 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1113 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:3241218 (3.2 MB)  TX bytes:114398 (114.3 KB)
          Interrupt:19 Base address:0xb000 

eth1      Link encap:Ethernet  HWaddr 00:0d:88:37:fa:22  
          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:17 Base address:0xc800 

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:22 errors:0 dropped:0 overruns:0 frame:0
          TX packets:22 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1220 (1.2 KB)  TX bytes:1220 (1.2 KB)

thufir at ARRAKIS:~$ 


A simple restart fixed the problem, hwat I have now seems exactly the 
same now:

thufir at ARRAKIS:~$ 
thufir at ARRAKIS:~$ sudo ifconfig
eth0      Link encap:Ethernet  HWaddr 00:16:ec:23:af:88  
          inet addr:70.71.111.41  Bcast:70.71.111.255  Mask:255.255.252.0
          inet6 addr: fe80::216:ecff:fe23:af88/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:123625 errors:0 dropped:0 overruns:0 frame:0
          TX packets:30935 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:61370499 (61.3 MB)  TX bytes:3480064 (3.4 MB)
          Interrupt:19 Base address:0xb000 

eth1      Link encap:Ethernet  HWaddr 00:0d:88:37:fa:22  
          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:17 Base address:0xc800 

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:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:440 (440.0 B)  TX bytes:440 (440.0 B)

thufir at ARRAKIS:~$ 


except that now I have internet access (obviously).  Why?  What did the 
restart accomplish?


thanks,

Thufir