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| − | [[Category:OPS335]][[Category:OPS335 Labs]] | + | #REDIRECT [[OPS335_Lab_2]] |
| − | {{Admon/caution|Draft:Do not use - Working in Progress|This warning message will be removed when it is ready.}}
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| − | ==IPTABLES - The Linux firewall==
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| − | In this lab you will learn how to use iptables to build a simple Linux firewall on your first Virtual Machine.
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| − | ==Instructions==
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| − | ===Verifying network connectivity to your VM===
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| − | * Boot up your Fedora Host.
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| − | * Login in to your Fedora host with your LearnID.
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| − | * Find out the MAC address of the virtual network device virbr0 and the IP address assigned to it. Record this information on your lab log book.
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| − | * Start the 1st VM.
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| − | ====On your VM ====
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| − | * Login with your LearnID to your VM.
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| − | * Open a terminal window and "su -" to root.
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| − | * Find out the MAC address of the NIC and the IP address assigned to it. Record this information on your lab log book.
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| − | * Disable your current firewall by flushing all rules in all chains in all tables and set up default policy for the INPUT, FORWARD, and OUTPUT chains to ACCEPT.
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| − | ====On your Fedora Host ====
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| − | * Open a terminal window and perform the following connectivity tests:
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| − | ** ping -c 2 [ip-of-vm1]
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| − | ** ssh [LearnID]@[ip-of-vm1]
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| − | ===Building a Simple Firewall on VM1 ===
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| − | '''On your VM1, on the "root" terminal, build a custom firewall by performing the following steps:'''
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| − | #Add appropriate rule(s) to allow all traffic to/from the loopback 'lo' interface.
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| − | #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.
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| − | #Add a rule to the INPUT chain of the filter table to allow all ESTABLISHED or RELATED incoming connections.
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| − | #Create a new chain named MYSSH in the filter table.
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| − | #Add a rule to the INPUT chain of your filter table that sends all tcp packets with destination port 22 to your MYSSH chain.
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| − | #Add a rule to your MYSSH chain to deny all traffic from 192.168.122.1 (i.e. your Fedora host). Also log these denied packets with log level 'info'.
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| − | #Add a rule to the INPUT chain of the filter table that allows all new tcp ssh connections.
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| − | #Make a new chain named MYICMP in the filter table.
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| − | #Add a rule to your MYICMP chain that denies ICMP pings from 192.168.122.1 (your Fedora host).
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| − | #Add a rule to your MYICMP chain that denies ICMP pings originating with MAC address of Fedora host's virbr0.
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| − | #Add a rule to your MYICMP chain that allows ICMP pings from anywhere.
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| − | #Add a rule to the INPUT chain of the filter table to send ICMP ping packets to your MYICMP chain.
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| − | #Change the default policy on the INPUT chain in the filter table to DROP.
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| − | ===Testing your custom firewall===
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| − | #Use nmap to scan your firewall from 192.168.122.1. If you don't have nmap on your system then install it.
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| − | #Use ping and ssh from 192.168.122.1 (and elsewhere) to verify your firewall is working properly. Be sure to check the log file for your unsuccessful ssh attempts.
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| − | #Save your firewall rules.
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| − | == Completing the Lab ==
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| − | Answer the following questions
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| − | #What is your full name and Seneca student ID?
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| − | #Show your firewall rules using the output of the 'iptables -L' command.
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| − | #Show the results of your nmap scans. Be sure to also show the exact nmap command you used.
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| − | #Show the log records generated by your invalid ssh attempts.
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| − | #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?
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