I have attached the topology, PC0 and PC1 are in same network (

PC0 send packet PC1 directly after arp resolution. So why router arp table shows PC0 and PC1 mac address. (Although the packet does not pass the router)enter image description here

  • but if hosts are in same network why they send the packet to default gateway ?
    – heavenix
    Commented Jun 22, 2018 at 8:36
  • 3
    communication between hosts will not reach the gateway. But can you be sure that no traffic at all was sent to the router? If the router is DHCP server and/or default gateway for example, you can be sure there was traffic. Any broadcast traffic coming from the PC's will reach the router as well.
    – Teun Vink
    Commented Jun 22, 2018 at 8:41
  • You really need to include the network device configurations.
    – Ron Maupin
    Commented Jun 22, 2018 at 14:45
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Commented Dec 25, 2018 at 8:54

2 Answers 2


If the hosts exchanged traffic with the router, which is very likely if you configured the router to be the default gateway for these PC's, the router will have learned their MAC addresses and will have stored their ARP entries.

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