Consider the network in Figure $1.$ It represents a small corporate network. The IP addresses are snown

e$)$ plicitly: MI to M$12$ mean

M$.$AC addresses, B$1.$ B$2$ and B$3$ are bridges. R$1.$ R$2$ and R$3$ are routers.

Figure$1.$ A small corporate network.

D$3$ is the DNS server for this network. The machines $C_1,D1,C2,D2,$ and $C_3$ are configured with

DNS server address $=192\mathrm{.}168\mathrm{.}1\mathrm{.}52.$

All interfaces that have IP addresses of the form $192\mathrm{.}168.$x$.$y are configured with netmash $=$

$255\mathrm{.}255\mathrm{.}255\mathrm{.}240.$

The default gateways are contigured as follows

at $Cl$ and $DI$:$192\mathrm{.}168\mathrm{.}1\mathrm{.}17$

$C_2$ and $D2$:$192\mathrm{.}168\mathrm{.}1\mathrm{.}33$