Dharani Dharan's questions

I have production network in some IP series say 192.168.X.X in Vmware. In this i have some machine. I need to create a test setup. I have created a separate VLAN. Those VLAN were not connected to any physical adapter. I call it as "ISOLATED ENV". i have created the same machines as prod in "ISOLATED ENV".

Physical_adpter----VLAN X ----> PROD_MACHINE          ISOLATED_ENV---->TEST_PROD_MACHI

i have gave same ip series in the production network to Isolated_Env. So ISOLATED_ENV machine IP's are same as production IP like 192.168.X.X.

Now i need to make a communication in between these network. i used a linux machine with 2 nic as router for this purpose.

But the issue, the communication will takes place either from one side. if i enabled the nic2 and gave the production network gateway is the IP in NIC2, the communication from Linux machine to ISOLATED_ENV will works. But I cant ping from prod network to Linux machine (Router).

How can i achieve this? i configured IP forwarding some other ip rules in the Linux machine.

If i configured this with 2 different networks means it will work. if i am giving the same ip address as prod it wont.

Help me out. Thanks in advance.

I am creating a test environment. In Which i have a production network,isolated network and linux machine. In Linux machine having 2 NICs, one NIC is connected to production network environment then assigned a IP and another one is Isolated network.

PROD-------(eth0)[LINUXMACHINE](eth1)-----ISOALTED NETWORK 

In the above representation, after configuring one NIC(eth0) , i can able to ping from production network machines to Linux Machine. Then am configured the eth1 to default gateway of the isolated network. After enabling eth1, can able to ping from and to Linux machine to Isolated env. Now I cant able to ping from Prod to Linux machine.If i am disabling the eth1 means, it will works otherwise it wont.

I am newbee to networking. I don't know exactly where is the issue and what i did wrong. I have enabled the following

IP Forwarding, MASQUERADE and some iptables rules

Anyone can suggest me a good way to make this work.

Thanks in advance

edited

ifconfig

eth0      Link encap:Ethernet  HWaddr 00:50:56:8f:68:e7  
          inet addr:192.168.108.13  Bcast:192.168.108.255  Mask:255.255.255.0
          inet6 addr: fe80::250:56ff:fe8f:68e7/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:335609 errors:0 dropped:3107 overruns:0 frame:0
          TX packets:48332 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:131610506 (131.6 MB)  TX bytes:4424737 (4.4 MB)

eth1      Link encap:Ethernet  HWaddr 00:50:56:8f:0a:c6  
          inet addr:192.168.103.1  Bcast:192.168.103.255  Mask:255.255.255.0
          inet6 addr: fe80::250:56ff:fe8f:ac6/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:18773 errors:0 dropped:0 overruns:0 frame:0
          TX packets:35645 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1816084 (1.8 MB)  TX bytes:50940327 (50.9 MB)

iptables -t nat -nvL

Chain PREROUTING (policy ACCEPT 3 packets, 375 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
   31  2604 DNAT       all  --  *      *       0.0.0.0/0            192.168.103.246      to:192.168.103.246

Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
 1985  138K MASQUERADE  all  --  *      eth0    0.0.0.0/0            0.0.0.0/0           
    0     0 MASQUERADE  all  --  *      eth0    0.0.0.0/0            0.0.0.0/0           

Chain VL (0 references)
 pkts bytes target     prot opt in     out     source               destination 

iptables -nvL

Chain INPUT (policy ACCEPT 49159 packets, 38M bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy ACCEPT 32 packets, 3393 bytes)
 pkts bytes target     prot opt in     out     source               destination         
13459  582K ACCEPT     all  --  eth1   *       0.0.0.0/0            0.0.0.0/0           
21264   38M ACCEPT     all  --  eth0   eth1    0.0.0.0/0            0.0.0.0/0            state RELATED,ESTABLISHED
    0     0 ACCEPT     all  --  eth1   eth0    0.0.0.0/0            0.0.0.0/0           

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
19109 1919K ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0 


cat /proc/sys/net/ipv4/ip_forward 1