MAC хаяг солигдсон үед CentOS, Redhat системд хийх тохиргоо

I was playing with My Virtualbox today and i tried to clone some Centos Servers. But after this, when starting the eth0, it is no more available.

check network:

# ifconfig

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:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0

          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

 Try to start Eth0 device

# ifup eth0
Device eth0 does not seem to be present, delaying initialisation

To Solve this :

Delete networking interface rules file so that it can be regenerated and reboot your CentOS system.

# rm /etc/udev/rules.d/70-persistent-net.rules
 reboot

New Mac address has been generated:

# This file was automatically generated by the /lib/udev/write_net_rules
 program, run by the persistent-net-generator.rules rules file.

 You can modify it, as long as you keep each rule on a single
 line, and change only the value of the NAME= key.
 PCI device 0x8086:0x100e (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="<span style="color: #ff0000">08:00:27:fe:c1:03</span>", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

Now edit /etc/sysconfig/network-scripts/ifcfg-eth0,

Add   new  HWADDR generated or  remove it 
Remove UUID   line

Restart the networking service

# service network restart
Shutting down interface eth0:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:                            [  OK  ]
Bringing up interface eth0:  Determining if ip address 192.168.1.99 is already in use for device eth0...

                                                           [  OK  ]

# ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:27:FE:C1:03
          inet addr:192.168.1.99  Bcast:xxxxxxxx  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fefe:c103/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4400 errors:0 dropped:0 overruns:0 frame:0
          TX packets:129 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000

          RX bytes:387597 (378.5 KiB)  TX bytes:19567 (19.1 KiB)

Enjoy!