#Login as joker to your Fedora 13 PC. NOTE: It's not necessary to use a VM for this lab. Just use your original Fedora system created in lab #0.

#Disable your current firewall. *i.e. flush all rules in all chains in all tables.#Now build a custom firewall by performing the following steps:

Now build a custom firewall by performing the following steps: #Add appropriate rule(s) to allow all traffic to/from the loopback 'lo' interface.#Add a rule to the INPUT chain of the filter table to allow all UDP traffic coming from port 53. i.e. source port is 53.#Add a rule to the INPUT chain of the filter table to allow all ESTABLISHED or RELATED incoming connections.#Create a new chain named MYSSH in the filter table.#Add a rule to the INPUT chain of your filter table that sends all tcp packets with destination port 22 to your MYSSH chain.#Add a rule to your MYSSH chain to deny all traffic from 142.204.141.XXX (XXX is the PC beside you). Also log these denied packets with log level 'info'.#Add a rule to the INPUT chain of the filter table that allows all new tcp ssh connections.#Make a new chain named MYICMP in the filter table.#Add a rule to your MYICMP chain that denies ICMP pings from 142.204.141.XXX (the PC beside you).#Add a rule to your MYICMP chain that denies ICMP pings originating with MAC address of 11:22:33:44:55:66 (NOTE: to test this you'll have to change the MAC address of the PC beside you with the ifconfig command).#Add a rule to your MYICMP chain that allows ICMP pings from anywhere.#Add a rule to the INPUT chain of the filter table to send ICMP ping packets to your MYICMP chain.#Change the default policy on the INPUT chain in the filter table to DROP.