[CentOS-virt] Network Bridgeing

Mon Jun 9 19:38:50 UTC 2014
Ing. Ramon Resendiz <rresendiz at globaltrack.com.mx>

Hi Zoltan,

 

I did the eth0 bridge to br0. As you explain i did the assignment the ip
from eth0 to the br0 interface. And is working I could ping between
interface from IP eth0 (br0) to VM and from VM to IP eth0. As well I tried
to configure my VM with the valid IP address and the connectivity loss until
I get back to the original configuration (dhcp).

 

Here is my ifconfig output:

 

br0       Link encap:Ethernet  HWaddr 00:26:9E:XX:XX:XX

          inet addr:208.66.XX.XX  Bcast:208.66.XX.XX  Mask:255.255.255.248

          inet6 addr: fe80::226:9eff:fe82:5538/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:8096 errors:0 dropped:0 overruns:0 frame:0

          TX packets:10438 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0

          RX bytes:629208 (614.4 KiB)  TX bytes:6818121 (6.5 MiB)

 

eth0      Link encap:Ethernet  HWaddr 00:26:9E:XX:XX:XX

          inet6 addr: fe80::226:9eff:fe82:5538/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:6768417 errors:0 dropped:0 overruns:0 frame:0

          TX packets:1952736 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000

          RX bytes:9696354264 (9.0 GiB)  TX bytes:305746274 (291.5 MiB)

          Memory:df6e0000-df700000

 

eth0:1    Link encap:Ethernet  HWaddr 00:26:9E:XX:XX:XX

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:0 errors:0 dropped:0 overruns:0 frame:0

          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000

          RX bytes:0 (0.0 b)  TX bytes:468 (468.0 b)

          Memory:df6e0000-df700000

 

eth1      Link encap:Ethernet  HWaddr 00:26:9E:XX:XX:XX

          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)

          Memory:df660000-df680000

 

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:312493 errors:0 dropped:0 overruns:0 frame:0

          TX packets:312493 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0

          RX bytes:188275585 (179.5 MiB)  TX bytes:188275585 (179.5 MiB)

 

virbr0    Link encap:Ethernet  HWaddr 52:54:00:ED:EC:C7

          inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:67131 errors:0 dropped:0 overruns:0 frame:0

          TX packets:110832 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0

          RX bytes:4087482 (3.8 MiB)  TX bytes:163016646 (155.4 MiB)

 

vnet0     Link encap:Ethernet  HWaddr FE:54:00:85:AE:AF

          inet6 addr: fe80::fc54:ff:fe85:aeaf/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:2735 errors:0 dropped:0 overruns:0 frame:0

          TX packets:54661 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:500

          RX bytes:292355 (285.5 KiB)  TX bytes:2884496 (2.7 MiB)

 

Here is my brctrl show:

bridge name     bridge id               STP enabled     interfaces

br0             8000.00269e825538       no              eth0

virbr0          8000.525400edecc7       yes             virbr0-nic

                                                        vnet0

Here is my vm network config (Windows Server 2003 Standard x64):

Windows IP Configuration

 

DHCP: Yes

IP Address: 192.168.122.77

Subnet Mask: 255.255.255.0

Default Gateway: 192.168.122.1

DHCP Server: 192.168.122.1

DNS Server: 192.168.122.1

 

 

 

De: centos-virt-bounces at centos.org [mailto:centos-virt-bounces at centos.org]
En nombre de Zoltan Frombach
Enviado el: lunes, 09 de junio de 2014 01:03 a.m.
Para: Discussion about the virtualization on CentOS
Asunto: Re: [CentOS-virt] Network Bridgeing

 

You need to add eth0 to the bridge (br0) which you already did. But do NOT
assign an IP address to eth0. Instead, assign the host's IP to br0.
Then just use another of your IPs for your VM (which can also be called eth0
inside your VM).
This way your host and your VM(s) can communicate with each other via the
bridge.

Note: If you want to use more than one IP address to access your host, then
create alias interfaces on the host for the bridge such as br0:0, br0:1,
etc.
Do not create alias interfaces on eth0. Also do not create an alias
interface on your host for the IP(s) which you'll be using inside your
VM(s).

I hope this helps.

On 6/9/2014 2:30 AM, Ing. Ramon Resendiz wrote:

Hi,

 

I have the following issue i recently installed a VM with qemu and libvirtd,
everything is almost ok. The problem is that i have 5 usable IP address
(valid ip address on internet) for eth0, and i want to use one of this IP
for my VM (Windows 2008 Standard R2 by the way). I did the bridge between my
eth0 and br0, the VM could browse into internet and download patches, etc.
etc. 

 

I tried to use a networking alias, this is the network interface eth0 assign
a IP address and for the eth0:1 assign other IP address, and this bridged to
the br0 instead of eth0 to eth0:1; after restart the network service the
connectivity lost, and then get in back the original configuration
everything seems to work again. But my goal is not archived.

 

Goal:

 

eth0 must have a valid ip address to be accesed, eth0:1 (bridged to br0)
must have a valid address to be assigned to the VM. Through iptables assign
ACL to each IP address (valid IP address) depending of the services to host
(web server and db server,  rdp host) and between interfaces could be
possible to communicate between them (virtual host and virtual machine).

 

eth0: Virtual Host

eth0:1: Virtual  machine (bridged to br0)

 

Thank you very much for you time.

 

Best regards,

RR

 






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