Exercise $2$:

Using GNS$3,$ cable the network of Figure $5.$ The cloud is just symbolic and represents the Internet. Do not worry too much about it$.$ The computers $($PC$01,$ PC$02,$ and PC$03)$ are Debian boxes. Power on the router and configure it as specified in Figure $6.$

Figure $5$: Network of the First Experiment with DHCP

Router$>$ enable

Router$\backslash$# configure terminal

Router$($config$)\backslash$# hostname R$1```$

R$1($config$)$# ip domain name jsu.edu

R$1($config$)$# interface FastEthernet $0/0$

R$1($config$-$if$)$# ip address $10\mathrm{.}0\mathrm{.}0\mathrm{.}1255\mathrm{.}255\mathrm{.}255\mathrm{.}0$

R$1($config$-$if$)$# no shutdown

R$1($config$-$if$)$# exit

R$1($config$)$# ip dhcp pool MYPOOL

R$1($dhcp$-$config$)$# network $10\mathrm{.}0\mathrm{.}0\mathrm{.}0255\mathrm{.}255\mathrm{.}255\mathrm{.}0$

R$1($dhcp$-$config$)$# domain$-$name jsu.edu

R$1($dhcp$-$config$)$# default$-$router $10\mathrm{.}0\mathrm{.}0\mathrm{.}1$

R$1($dhcp$-$config$)$# dns$-$server $8\mathrm{.}8\mathrm{.}8\mathrm{.}8$

R$1($dhcp$-$config$)$# lease $0010$

R$1($dhcp$-$config$)$# end

R$1$# show ip dhcp pool

R$1$# show ip dhcp binding

$```$

Figure $6$: Configuration of the Router for the First Experiment with DHCP

Question $2\mathrm{.}1$:

Start capturing the network traffic with Wireshark in any link connected to the hub. Power on PCO$1.$ Make sure it gets its network configuration through DHCP$.$ Check the DORA $($DHCPDISCOVER$/$DHCPOFFER$/$DHCPREQUEST$/$ DHCPACK$)$ exchange in Wireshark. Give as much information as you can about the DORA exchange. Keep capturing for at least $15$ minutes. Check the renewal of the lease. How frequent is the renewal? What are the messages involved? Check the DHCP pool $($show ip dhep pool$)$ and the DHCP binding $($show ip dhep binding$)$ in the router. The "debug ip dhcp server events" command can be extremely useful when troubleshooting DHCP leases with a Cisco IOS DHCP server. You have to enter this command in the privileged mode. Since the number of debugging messages can be overwhelming, you can stop the debugging process with $"$no debug ip dhcp server events" or with $"$no debug all".

Question $2\mathrm{.}2$:

Power on PCO$2.$ What is the IP address obtained by this computer? Check the DHCP pool and the DHCP binding in the router. Power on PCO$3.$ What is the IP address obtained by this computer? Check the DHCP pool and the DHCP binding in the router.