bridge network between two linux servers

Question

I need to set up following network architecture :

                       Internet
                        ^   
+-----------------+     |          +------------------+
|  Centos6-1      |     |          |      Centos6-2   |
|      +---- eth0 + ----+          |                  |
| (br0)|          |                |                  |
|      +---- eth1 +----------------+ eth0             |
+-----------------+                +------------------+
                     ( cable connection )

Two public IP's are to be configured like follows :

eth0 and eth1 of **Centos6-1 are to be configured as a bridge with IP1
Centos6-1 can be accessed with IP1
eth0 of Centos6-2 is configured with IP2
any request destined to IP2 will flow through Centos6-1

How can i accomplish this feat?

There is a service running in the second server. This service will bind to IP2. what will happen

Edit:

If i do the following in box1:

brctl addbr br0
ifdown eth0
ifdown eth1
ifconfig eth0 0.0.0.0 up
ifconfig eth1 0.0.0.0 up
ifconfig br0 IP1 ****

would it do what i want?

Putting ASCII diagrams in your questions is asking for free +1's on ServerFault -- welcome aboard! — Kyle Smith, Apr 16 '12 at 14:42
it will flow thru Centos6-1 but only at the link layer. sort of like using your Centos6-1 as a network switch. — sybreon, Apr 17 '12 at 04:24

score 2 · Answer 1 · answered Apr 16 '12 at 13:58

2

That's not bridging, what you want is simple NAT forwarding.

iptables -t nat -A PREROUTING -i eth0 -d IP2 --to-destination internal_IP2 -j DNAT

And let the boxes communicate using a private internal_IP pair (internal_IP1, internal_IP2)

answered Apr 16 '12 at 13:58

adaptr

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does this leave the packets verbatim or modify packet header? I'm going for link layer because i want my packets intact. – Aftnix Apr 16 '12 at 15:00
It changes the destination IP of the incoming packets, and the source IP of the outgoing packets. Why do you think this is a problem ? – adaptr Apr 16 '12 at 15:20

score 2 · Accepted Answer · answered Apr 16 '12 at 14:35

According to this blog, you can setup bridge under CentOS in this way:

You have to add /etc/sysconfig/network-scripts/ifcfg-br0:

DEVICE=br0
TYPE=Bridge
BOOTPROTO=static
DNS1=192.168.0.1
GATEWAY=192.168.0.1
IPADDR=192.168.0.100
NETMASK=255.255.255.0
ONBOOT=yes
SEARCH=”example.com”

And in the ifcfg-eth0:

DEVICE=eth0
HWADDR=00:1e:90:f3:f0:02
ONBOOT=yes
TYPE=Ethernet
IPV6INIT=no
USERCTL=no
BRIDGE=br0

ifcfg-eth1 will be similar.

HWADDR you have to have MAC address of eth0, resp. eth1...

Between two servers you have to have crossover Ethernet cable...

bridge network between two linux servers

2 Answers2