Linux :service network restart :bringing up interface eth0:unknown connection

暑假开始拿了本linux的书自虐，在安装gnome桌面环境之后，service network restart之后又发现bringing up interface eth0:unknown connection 【Failed】

我只是用vi /etc/sysconfig/network-scripts/ifcfg-eth0修改了ip而已啊，报的错误是未知连接然后是uuid，同时ifconfig也不能显示eth0的ip。

并不知道uuid是什么鬼，嗯，直接注释掉，然后问题居然就解决了。只是不能restart。not active。。。

[root@localhost Desktop]# service network restart
Shutting down interface eth0: Error: Device \'eth0\' (/org/freedesktop/NetworkManager/Devices/0) disconnecting failed: This device is not active
                                                           [FAILED]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Error: Connection activation failed: Device not managed by NetworkManager or unavailable
                                                           [FAILED]
[root@localhost Desktop]# chkconfig NetworkManager off
[root@localhost Desktop]# chkconfig network on
[root@localhost Desktop]# service NetworkManager stop
Stopping NetworkManager daemon: [ OK ]
[root@localhost Desktop]# service network start
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
[root@localhost Desktop]# service network restart
Shutting down interface eth0: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: [ OK ]
[root@localhost Desktop]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0C:29:A0:C6:44 
          inet addr:192.168.1.189 Bcast:192.168.1.255 Mask:255.255.255.0
          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)

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:12 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:720 (720.0 b) TX bytes:720 (720.0 b)

[root@localhost Desktop]# iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination 
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED 
ACCEPT icmp -- anywhere anywhere 
ACCEPT all -- anywhere anywhere 
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh 
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited 

Chain FORWARD (policy ACCEPT)
target prot opt source destination 
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited 

Chain OUTPUT (policy ACCEPT)
target prot opt source destination 
[root@localhost Desktop]# iptables -F

然后以上一番操作解决问题，谜一样的Linux，然后把uuid注释去掉仍然正常运行网络服务。万一哪个大神看到了能不能告诉我为什么我把uuid注释掉了还可以正常运行？上面的一番操作是为何解决问题的？感激不尽TAT

上述操作来自http://blog.itpub.net/27099995/viewspace-1107909/  侵权删，，求饶过