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I am presently configuring a firewall with 3 nics. One connect to the internet, one to DMZ and one to private network. Eventually, the nic for both DMZ and internet had to be of the same subnet. Hence, I configured the network as the picture below.<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Internet<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;|<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;|<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;|<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 192.168.40.2<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;------------ &nbsp; 192.168.40.4<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;| Firewall &nbsp;|/<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;|-----------|----------DMZ<wbr />-------<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;| &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; |192.168.40.10<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;| &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Server<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; private network<br />
The problem is that the nic for the internet and nic for DMZ has a conflict. As the server can ping 192.168.40.4 but not the other way round. However once the nic to internet is disable they can ping each other. How should I go around this?
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I am presently configuring a firewall with 3 nics. One connect to the internet, one to DMZ and one to private network. Eventually, the nic for both DMZ and internet had to be of the same subnet. Hence, I configured the network as the picture below.
                       Internet
                           |
                           |
                           |
                  192.168.40.2
                     ------------   192.168.40.4
                     | Firewall  |/
                     |-----------|----------DMZ-------
                           |             |192.168.40.10
                           |          Server
                        private network
The problem is that the nic for the internet and nic for DMZ has a conflict. As the server can ping 192.168.40.4 but not the other way round. However once the nic to internet is disable they can ping each other. How should I go around this?

Same subnet for 2 NIC in a system

The variety of Linux distributions creates myriad issues relating to configuration and operations when computers are networked, not the least of which is the use of various network management applications, some of which are included with specific distributions, while others are standalone applications.