Forwarding ICMP response to TAP interface












1















I am trying to do a test where I forward ICMP responses to a TAP interface. I created a TAP interface and assigned it the address 10.0.4.1/24.



My linux setup uses the interface enp0s3 as the default option. To forward any ICMP response to the TAP interface, I tried the following rules:



# iptables -t nat -A PREROUTING -i enp0s3 -p icmp -j DNAT --to 10.0.4.1

# iptables -A FORWARD -p icmp -i enp0s3 -j ACCEPT

# iptables -t nat -A POSTROUTING -o 10.0.4.1 -j MASQUERADE


At the moment, the TAP interface is in UP state, and I have a program which is listening to the TAP interface.



If I ping an external IP like 8.8.8.8, I still am able to get the response. I want to ask shouldn't the ping program not receive any response because ICMP response is getting forwarded to the TAP interface ? Also, is my approach to redirect traffic to the TAP device correct ?






netfilter icmp tap







share|improve this question





























    1















    I am trying to do a test where I forward ICMP responses to a TAP interface. I created a TAP interface and assigned it the address 10.0.4.1/24.



    My linux setup uses the interface enp0s3 as the default option. To forward any ICMP response to the TAP interface, I tried the following rules:



    # iptables -t nat -A PREROUTING -i enp0s3 -p icmp -j DNAT --to 10.0.4.1
    
# iptables -A FORWARD -p icmp -i enp0s3 -j ACCEPT
    
# iptables -t nat -A POSTROUTING -o 10.0.4.1 -j MASQUERADE


    At the moment, the TAP interface is in UP state, and I have a program which is listening to the TAP interface.



    If I ping an external IP like 8.8.8.8, I still am able to get the response. I want to ask shouldn't the ping program not receive any response because ICMP response is getting forwarded to the TAP interface ? Also, is my approach to redirect traffic to the TAP device correct ?






    netfilter icmp tap







    share|improve this question



























      1












      1








      1








      I am trying to do a test where I forward ICMP responses to a TAP interface. I created a TAP interface and assigned it the address 10.0.4.1/24.



      My linux setup uses the interface enp0s3 as the default option. To forward any ICMP response to the TAP interface, I tried the following rules:



      # iptables -t nat -A PREROUTING -i enp0s3 -p icmp -j DNAT --to 10.0.4.1
      
# iptables -A FORWARD -p icmp -i enp0s3 -j ACCEPT
      
# iptables -t nat -A POSTROUTING -o 10.0.4.1 -j MASQUERADE


      At the moment, the TAP interface is in UP state, and I have a program which is listening to the TAP interface.



      If I ping an external IP like 8.8.8.8, I still am able to get the response. I want to ask shouldn't the ping program not receive any response because ICMP response is getting forwarded to the TAP interface ? Also, is my approach to redirect traffic to the TAP device correct ?






      netfilter icmp tap







      share|improve this question
















      I am trying to do a test where I forward ICMP responses to a TAP interface. I created a TAP interface and assigned it the address 10.0.4.1/24.



      My linux setup uses the interface enp0s3 as the default option. To forward any ICMP response to the TAP interface, I tried the following rules:



      # iptables -t nat -A PREROUTING -i enp0s3 -p icmp -j DNAT --to 10.0.4.1
      
# iptables -A FORWARD -p icmp -i enp0s3 -j ACCEPT
      
# iptables -t nat -A POSTROUTING -o 10.0.4.1 -j MASQUERADE


      At the moment, the TAP interface is in UP state, and I have a program which is listening to the TAP interface.



      If I ping an external IP like 8.8.8.8, I still am able to get the response. I want to ask shouldn't the ping program not receive any response because ICMP response is getting forwarded to the TAP interface ? Also, is my approach to redirect traffic to the TAP device correct ?






      netfilter icmp tap




      netfilter icmp tap






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited 50 mins ago







      Jake

















      asked 6 hours ago









      JakeJake

      539722




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