Changes

=== Investigation 2: How do you configure a static network using <code>system-config-network</code>. ===

# Start '''centos2''' VM and login

# On your '''centos host''' run <code>ifconfig</code> and make note of the IP address assigned to the <code>virbr1</code> interface. This will be the default gateway and DNS server for your VMs.[[Image:new_network_dialog.png|thumb|350px]]

#: IP Address '''192.168.235.12'''

#: Subnet Mask '''255.255.255.0'''

# Your network connection may take a couple of minutes to reconfigure connect (view the Network Manager applet in the gnome panel at the top of the screen).

# You should be able to use the systemctl command to restart your network.

#*<code>service network stop</code>

#*<code>service network start</code>

=== Investigation 4: How do I configure the network without a GUI tool? ===

# Start '''centos3''' VM and login as root

# Use the command <code>ifconfig</code> to list active interfaces, you should see one with a name of <code>eth0</code> or a similar name.

#* <code>ifconfig</code>

#* <code>route -n</code>

#* <code>ssh</code> to your matrix account to test DNS

# Restart the <code>centos3</code> VM, or just wait a few minutes.

=== Investigation 5: How do I setup local hostname resolution? ===

{{Admon/note | Hosts files vs. the Domain Name System | On large public networks like the Internet or even large private networks we use a network service called [http://en.wikipedia.org/wiki/Domain_Name_System Domain Name System (DNS)] to resolve the human friendly hostnames like '''centos.org''' to the numeric addresses used by the IP protocol. On smaller networks we can use the <code>/etc/hosts</code> on each system to resolve names to addresses.}}

# Use the <code>hostname</code> and <code>ifconfig</code> commands on your centos host and all 3 VM's to gather the information needed to configure the <code>/etc/hosts</code> file on the centos host and the 3 VM's.

|

<pre>

192.168.235.1 c6host

=== Investigation 6: How do I collect the MAC (Hardware) addresses of computers on my network? ===

{{Admon/note | Obtaining Remote MAC Addresses| The term '''MAC''' address stands for '''Media Access Control''' address, which provides a unique ID to prevent confusion among computer systems within a network. While we use '''32bit IP addresse'''s to communicate over an internet, on the local ethernet network packets are delivered to a '''48bit hardware address''' (sometimes called a MAC address). The '''ARP''' protocol resolves 32bit IP addresses to 48bit MAC addresses by using a broadcast and caching the results. We can examine the ARP cache to get the MAC addresses of other computers on our local network.<br /><br />Being able to determine remote MAC address information is useful from troubleshooting networking programs to using '''WOL''' (Wake up on Lan) to automatically boot remote workstations via the network. In this investigation, you will learn how to obtain MAC address information for various network cards.}}

=== Investigation 7: How can I see what network services or ports are active on my CentOS system? ===

{{Admon/note | Network Ports | When our CentOS system provides any services on a network, those services are accessible through a port number. All network services are configured to be accessed on a particular port number. By examining which ports are active on our system we can know what services (and points of attack) are available on our system. The ability to examine this information is important for troubleshooting network services and securing our systems. One great tool for this is the <code>netstat</code> command.}}

# TCP is a connection oriented protocol that uses a handshaking mechanism to establish a connection. Those ports that show a state of LISTEN are waiting for connection requests to a particular service. For example you should see the <code>ssh</code> service in a LISTEN state as it is waiting for connections.

# From one of your VM's login to your host using <code>ssh</code>

# Without the <code>-n</code> option <code>netstat</code> attempts to resolve IP addresses to host names (using /etc/hosts) and port numbers to service names (using /etc/services)

# Examine the <code>/etc/services</code> file and find which ports are used for the services: <code>ssh, ftp, http</code>

It should be noted that all of the commands that we do here with iptables will not be persistent unless you have your configuration. That means if you re-boot, the default iptables configuration will be loaded.}}

#* <code>iptables -F</code> (This flushes out or clears all of your rules from the chains)

#* <code>iptables -L</code>

# Confirm that your rule works by testing from your VM's

# Does iptables close the port? Check using <code>netstat</code>

# Fully test your configuration.