Proxy ARP and this scenarion

[zillah2004]

I want to ensure that HostA has connectivity with HostB. HostA and HostB are

connected via RouterA (RA) and RouterB (RB).

HostA has ip an address 10.1.1.10/8 and connected to RA via his fastethernet interface 10.1.1.1/24.

RA connected via its serial interface (10.1.2.1/24) to router RB via his serial interface 10.1.2.2/24.

HostB has an ip address 10.1.3.1/24 and connected to RB via his fastethernet interface

No routing protocols or static routes are configured on either RA or RB.

To enable HostA to send packets to HostB Why does HostA must have a default gateway address of 10.1.1.1 ? or Does HostB must have a default gateway address of 10.1.3.1?

Does we need to enable Proxy ARP RouterA (ARP)?

[jeff-krauss]

Since Host A is in a /8 subnet, it believes that 10.1.3.x is located in its local subnet. Therefore, it does not see a need to send the ping to its default gateway.

Instead, it should ARP, and if RA knows where 10.1.3.1 is, it can Proxy ARP for it.

However, you've said that no routing protocols or static routes are configured on RA, so it doesn't know where 10.1.3.1 is located.

Consequently, if you want RA to respond with a Proxy ARP for 10.1.3.1, then RA will have to learn the route to 10.1.3.1 (or have a default route)

Additionally, in this scenario, Host B will have to know how to get back to 10.1.1.10, as will its router, RB.