View source for OPS335 Firewall Lab

[[Category:OPS335]][[Category:OPS335 Labs]]

==Basic IP Tables==

In this lab you will learn how to use iptables to build a simple Linux firewall.


==Instructions==
===Building a Simple Firewall===
#Login as joker to your Fedora 13 PC.
#*It's not necessary to use a VM for this lab. Just use your original Fedora system created in lab #0.
#Open a terminal window and "su -" to root.
#Disable your current firewall. i.e. flush all rules in all chains in all tables.
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.
===Testing your custom firewall===
#Use nmap to scan your firewall from 142.204.141.XXX. If you don't have nmap on your system then install it.
#Use ping and ssh from 142.204.141.XXX (and elsewhere) to verify your firewall is working properly. Be sure to check the log file for your unsuccessful ssh attempts.
#Save your firewall rules.

== Completing the Lab ==
Answer the following questions
#What is your full name and Seneca student ID?
#Show your firewall rules using the output of the iptables-save command.
#Show the results of your nmap scans. Be sure to also show the exact nmap command you used.
#Show the log records generated by your invalid ssh attempts.
#What iptables rule would you need to add to your firewall to allow a maximum of 3 concurrent ssh connections from 142.204.141.XXX to your host?