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I have a question when a Router receives ARP request to a host that dosen't exists on the forwarding table for that router does the.

And this Router is not the next hop either will the Router continue to send this ARP request or will the Router Discard the ARP-request?

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    Your first sentence seems to be cut off in the middle. You had better wording before you edited it. – Barmar Sep 12 '20 at 5:28
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I think you are confused about ARP requests. ARP requests are sent from a source host to the broadcast address, and every host on the broadcast domain will inspect the request. Only the host with the IPv4 address in the ARP request will reply. All other hosts on the broadcast domain will ignore the request.

For a layer-2 broadcast domain, a router is just another host, so unless the ARP request is for the router itself, then the router will ignore the ARP request. Because ARP requests are broadcast, they are not routed to any other network.

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  • Thanks Ron for the help! – Jonte YH Sep 11 '20 at 19:29
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    Ron's right for just about anything you'd see in the wild, but the exception (it's networking - there's almost always an exception) to what he's described is proxy arp, where a router may respond with its address for hosts outside the subnet. See en.wikipedia.org/wiki/Proxy_ARP for a decent treatment of the subject. – rnxrx Sep 11 '20 at 23:25
  • @rnxrx, I believe that the OP is referring to a router not directly attached to the network: "And this Router is not the next hop either." I contemplated mentioning proxy ARP, but I thought it may confuse the situation more for the OP. It sounded to me like he assumed ARP requests were bouncing from router to router, looking for a host: "a host that dosen't exists on the forwarding table for that router." – Ron Maupin Sep 13 '20 at 0:10

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