How can a UDP Client and a packet sniffer run on the same machine?












3














In my understanding, if you have a UDP socket client that is bound to a particular port, then a second UDP client on the same machine can't bind to the same port.



If this is the case, then how can a packet sniffing program like Wireshark run on the same machine you have a UDP client without issues?










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    3














    In my understanding, if you have a UDP socket client that is bound to a particular port, then a second UDP client on the same machine can't bind to the same port.



    If this is the case, then how can a packet sniffing program like Wireshark run on the same machine you have a UDP client without issues?










    share|improve this question



























      3












      3








      3







      In my understanding, if you have a UDP socket client that is bound to a particular port, then a second UDP client on the same machine can't bind to the same port.



      If this is the case, then how can a packet sniffing program like Wireshark run on the same machine you have a UDP client without issues?










      share|improve this question















      In my understanding, if you have a UDP socket client that is bound to a particular port, then a second UDP client on the same machine can't bind to the same port.



      If this is the case, then how can a packet sniffing program like Wireshark run on the same machine you have a UDP client without issues?







      wireshark udp packet-analysis layer4 transport-protocol






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      edited Dec 14 at 6:18









      Ron Maupin

      61.7k1162114




      61.7k1162114










      asked Dec 13 at 21:46









      Fred

      1185




      1185






















          1 Answer
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          6














          Packet sniffing applications tap into the lower layers of the network stack, not at the top like your UDP-using applications that connect to UDP at the top of the network stack.






          share|improve this answer























          • Are you saying that the packet sniffing applications work at the network/routing layer?
            – Fred
            Dec 13 at 22:04










          • Even lower than that. Most can capture the Data-Link frames.
            – Ron Maupin
            Dec 13 at 22:05






          • 1




            @Fred Usually the packet capturing happens right on top of the NIC, ie. between layer 2 and 3.
            – Zac67
            Dec 13 at 22:11













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          1 Answer
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          active

          oldest

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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          6














          Packet sniffing applications tap into the lower layers of the network stack, not at the top like your UDP-using applications that connect to UDP at the top of the network stack.






          share|improve this answer























          • Are you saying that the packet sniffing applications work at the network/routing layer?
            – Fred
            Dec 13 at 22:04










          • Even lower than that. Most can capture the Data-Link frames.
            – Ron Maupin
            Dec 13 at 22:05






          • 1




            @Fred Usually the packet capturing happens right on top of the NIC, ie. between layer 2 and 3.
            – Zac67
            Dec 13 at 22:11


















          6














          Packet sniffing applications tap into the lower layers of the network stack, not at the top like your UDP-using applications that connect to UDP at the top of the network stack.






          share|improve this answer























          • Are you saying that the packet sniffing applications work at the network/routing layer?
            – Fred
            Dec 13 at 22:04










          • Even lower than that. Most can capture the Data-Link frames.
            – Ron Maupin
            Dec 13 at 22:05






          • 1




            @Fred Usually the packet capturing happens right on top of the NIC, ie. between layer 2 and 3.
            – Zac67
            Dec 13 at 22:11
















          6












          6








          6






          Packet sniffing applications tap into the lower layers of the network stack, not at the top like your UDP-using applications that connect to UDP at the top of the network stack.






          share|improve this answer














          Packet sniffing applications tap into the lower layers of the network stack, not at the top like your UDP-using applications that connect to UDP at the top of the network stack.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Dec 14 at 6:21

























          answered Dec 13 at 21:51









          Ron Maupin

          61.7k1162114




          61.7k1162114












          • Are you saying that the packet sniffing applications work at the network/routing layer?
            – Fred
            Dec 13 at 22:04










          • Even lower than that. Most can capture the Data-Link frames.
            – Ron Maupin
            Dec 13 at 22:05






          • 1




            @Fred Usually the packet capturing happens right on top of the NIC, ie. between layer 2 and 3.
            – Zac67
            Dec 13 at 22:11




















          • Are you saying that the packet sniffing applications work at the network/routing layer?
            – Fred
            Dec 13 at 22:04










          • Even lower than that. Most can capture the Data-Link frames.
            – Ron Maupin
            Dec 13 at 22:05






          • 1




            @Fred Usually the packet capturing happens right on top of the NIC, ie. between layer 2 and 3.
            – Zac67
            Dec 13 at 22:11


















          Are you saying that the packet sniffing applications work at the network/routing layer?
          – Fred
          Dec 13 at 22:04




          Are you saying that the packet sniffing applications work at the network/routing layer?
          – Fred
          Dec 13 at 22:04












          Even lower than that. Most can capture the Data-Link frames.
          – Ron Maupin
          Dec 13 at 22:05




          Even lower than that. Most can capture the Data-Link frames.
          – Ron Maupin
          Dec 13 at 22:05




          1




          1




          @Fred Usually the packet capturing happens right on top of the NIC, ie. between layer 2 and 3.
          – Zac67
          Dec 13 at 22:11






          @Fred Usually the packet capturing happens right on top of the NIC, ie. between layer 2 and 3.
          – Zac67
          Dec 13 at 22:11




















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