Basic CS-Networks [3i Infotech Placement]: Sample Questions 85 - 85 of 90

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Question 85

Networks
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Describe in Detail

Essay▾

What is Proxy ARP?

Explanation

Define Proxy ARP
  • Proxy ARP allows a device on a network to answer ARP queries for an IP address not on the network.
  • For example, using a router to answer ARP request.
  • Used when the originating host believes that a destination is local, when in fact it is lies beyond the router.
  • Allows machines on a subnet to reach remote subnets without need to configure routing or a default gateway.

Advantages:

  • It can be added to a single router on a network without disturbing routing tables of other routers on the network.
  • Used on the network where IP hosts are not configured with a default gateway or have no routing intelligence.

Disadvantages:

  • Increases amount of ARP traffic on segment.
  • Hosts need larger ARP tables to handle IP to MAC address mappings.
  • Does not work for networks that do not use ARP for address resolution.
  • Is not generalizable to all network topologies. For example, more than one router connecting two physical networks.

Use of proxy ARP:

  • Joins a broadcast LAN with serial links
  • Takes multiple addresses from a LAN
  • On a firewall
  • Mobile-IP
  • Transparent subnet gatewaying.

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