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 ?










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 ?










    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 ?










      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






      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




      539722






















          0






          active

          oldest

          votes











          Your Answer








          StackExchange.ready(function() {
          var channelOptions = {
          tags: "".split(" "),
          id: "106"
          };
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function() {
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled) {
          StackExchange.using("snippets", function() {
          createEditor();
          });
          }
          else {
          createEditor();
          }
          });

          function createEditor() {
          StackExchange.prepareEditor({
          heartbeatType: 'answer',
          autoActivateHeartbeat: false,
          convertImagesToLinks: false,
          noModals: true,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: null,
          bindNavPrevention: true,
          postfix: "",
          imageUploader: {
          brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
          contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
          allowUrls: true
          },
          onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          });


          }
          });














          draft saved

          draft discarded


















          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f507808%2fforwarding-icmp-response-to-tap-interface%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          0






          active

          oldest

          votes








          0






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes
















          draft saved

          draft discarded




















































          Thanks for contributing an answer to Unix & Linux Stack Exchange!


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          To learn more, see our tips on writing great answers.




          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f507808%2fforwarding-icmp-response-to-tap-interface%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown





















































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown

































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown







          Popular posts from this blog

          サソリ

          広島県道265号伴広島線

          Setup Asymptote in Texstudio