Week10-Lab-build a network with switch and observe MAC Addresses and ARP PDF

Title Week10-Lab-build a network with switch and observe MAC Addresses and ARP
Author Zihao Cui
Course Networking Fundamentals
Institution University of Technology Sydney
Pages 11
File Size 918.7 KB
File Type PDF
Total Views 134

Summary

week 10 tutorial work...


Description

Week 2 Lab – Observing MAC Addresses and ARP Topology

Addressing Table Device

Interface

IP Address

Subnet Mask

Default Gateway

S1

VLAN1

192.168.1.11

255.255.255.0

N/A

S2

VLAN1

192.168.1.12

255.255.255.0

N/A

PC-A

NIC

192.168.1.3

255.255.255.0

192.168.1.1

PC-B

NIC

192.168.1.2

255.255.255.0

192.168.1.1

Objectives Part 1: Get Familiar with Cisco Packet Tracer Part 2: Set Up the Topology and Initialize Devices Part 3: Configure Devices and Verify Connectivity Part 4: Display, Describe, and Analyze Ethernet MAC Addresses Part 5: Use the IOS Show ARP Command

Required Resources 

Cisco netcad account



Cisco Packet Tracer 7.3.0

Part 1: Get familiar with Cisco Packet Tracer Step 1: Register CISCO account a. Go to https://www.netacad.com/ and create an account. b. Download CISCO Packet Tracer 7.3.0 fitting your system https://www.netacad.com/portal/resources/packettracer.

c.

Install the Packet Tracer, Open the Packet Tracer and Log in with your account. You will see the Cisco Packet Tracer as below.

A tutorial of Packet Tracer can be found here http://static-pt-assets.s3.amazonaws.com/tutorials72.htm

Part 1: Set Up the Topology and Initialize Devices In Part 1, you will set up the network topology, clear any configurations, if necessary, and configure basic settings, such as the interface IP addresses on the router and PCs.

Step 1: Cable the network as shown in the Topology. a. Attach the devices shown in the Topology and cable as necessary. b. Power on all the devices in the topology. Build the network as shown in the Topology using Packet Tracer. From the bottom-left Device Box, choose “Network Devices” -> “Switch-PT” -> “2960” and drag the switch to your canvas as the S1 and S2.

And from “End Devices” choose “End Devices” -> “PC”, as your PC-A and PC-B:

From the “Connections”, select the corresponding “Copper Straight-Through” and “Copper Cross-Over” cables to connect the swtiches and PCs, and the two switches using the corresponding ports as shown in the Toplogy. Select the cable first, then click the devices to be connected and select given interface.

PS. Select “Options” -> “Preferences” to uncheck “Show Device Model Labels” and check “Show Device Name Labels” and “Always Show Port Label in Logical Workspace”.

Step 2: Establish console connection and initialize and reload the switches. Before starting a hands-on lab that makes use of either a Cisco router or switch, you should ALWAYS ensure that the devices in use have been erased and have no startup configurations present. Otherwise, the results of your lab may be unpredictable. Make sure that the switches have been erased and have no startup configurations. If you are unsure, refer to Appendix A for detailed steps for initializing switches. If the switches have been password protected, refer to Appendix B for password recovery.

Part 2: Configure Devices and Verify Connectivity In Part 2, you will configure basic settings, such as the interface IP addresses and device access. For device names and address information, refer to the Topology and Addressing Table.

Step 1: Configure basic settings for the switch S1. In this step, you will configure the device name and the IP address, and disable DNS lookup on the switch S1. a. Console into the switch and enter global configuration mode. PS. How to console into the switch: Connect to the switch S1’s Console port using a serial console cable from PC-A communication port, and open PuTTy on the desktop of PC-A (connect via Serial).

In Packet Tracer, click the switch and from the open dialog, click the “CLI” tap on the top to enter the CLI of the switch. Hit the Enter key on your keyboard when the dialog is active and then you will see the system prompt “Switch>”. The console connection is ready for you to proceed with the rest switch configuration. PS, click the “Config” tab and you may change the display name of the devices.

Switch> enable Switch# configure terminal Enter configuration commands, one per line.

End with CNTL/Z.

Switch(config)# b. Assign a hostname to the switch based on the Addressing Table. Switch(config)# hostname S1 c.

Disable DNS lookup. S1(config)# no ip domain-lookup

d. Configure and enable the SVI interface for VLAN 1. S1(config)# interface vlan 1 S1(config-if)# ip address 192.168.1.11 255.255.255.0 S1(config-if)# no shutdown S1(config-if)# end *Mar

1 00:07:59.048: %SYS-5-CONFIG_I: Configured from console by console

Step 2: Configure basic settings for the switch S2. In this step, you will configure the device name and the IP address, and disable DNS lookup on the switch S2. a. Console into the switch and enter global configuration mode.

PS. How to console into the switch: Connect to the switch S2’s Console port using a serial console cable from PC-B communication port, and open PuTTy on the desktop of PC-B (connect via Serial).

Switch> enable Switch# configure terminal Enter configuration commands, one per line. Switch(config)#

End with CNTL/Z.

b. Assign a hostname to the switch based on the Addressing Table. Switch(config)# hostname S2 c.

Disable DNS lookup. S2(config)# no ip domain-lookup

d. Configure and enable the SVI interface for VLAN 1. S2(config)# interface vlan 1 S2(config-if)# ip address 192.168.1.12 255.255.255.0 S2(config-if)# no shutdown S2(config-if)# end *Mar

1 00:07:59.048: %SYS-5-CONFIG_I: Configured from console by console

Step 3: Configure the IPv4 addresses for the PCs. a. Configure the IPv4 address, subnet mask, and default gateway address for PC-A and PC-B according to the Addressing Table. In Packet Tracer, click PC-A (do the same for PC-B after). On the open dialog, click the “Desktop” tap and then “IP Configuration” box to configure the PC’s IP address information according to the Addressing Table:

b. Open the Window’s command prompt (cmd.exe) and type ipconfig /all to verify the IP configuration of the hosts. PS. In Packet Tracer, click PC-A (do the same for PC-B after). On the open dialog, click the “Desktop” tap and then “Command Prompt” box to open the Window’s Command Prompt (cmd.exe) and run the Windows cmd commands.

Step 4: Verify network connectivity. a. Ping the switches VLAN1 from each of PC-A and PC-B’s command prompt. Were the pings successful? Yes, the pings are successful If not, check your cabling and configuration and ask your instructor for help.

Part 3: Display, Describe, and Analyze Ethernet MAC Addresses Every device on an Ethernet LAN has a MAC address that is assigned by the manufacturer and stored in the firmware of the NIC. Ethernet MAC addresses are 48-bit long. They are displayed using six sets of hexadecimal digits that are usually separated by dashes, colons, or periods. The following example shows the same MAC address using the three different notation methods: 00-05-9A-3C-78-00

00:05:9A:3C:78:00

0005.9A3C.7800

Note: MAC addresses are also called physical addresses, hardware addresses, or Ethernet hardware addresses. You will issue commands to display the MAC addresses on a PC and a switch, and analyze their properties.

Step 1: Analyze the MAC address for PC-A’s and PC-B’s NICs. Before you analyze the MAC address on PC-A, look at an example from a different PC NIC. You can issue the ipconfig /all command to view the MAC address of your NIC. An example screen output is shown below. C:\> ipconfig /all

Ethernet adapter Ethernet: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Intel(R) 82577LM Gigabit Network Connection Physical Address. . . . . DHCP Enabled. . . . . . . Autoconfiguration Enabled Link-local IPv6 Address . IPv4 Address. . . . . . .

. . . . .

. . . . .

. . . . .

. . . . .

: : : : :

5C-26-0A-24-2A-60 Yes Yes fe80::b875:731b:3c7b:c0b1%10(Preferred) 192.168.1.2(Preferred)

Subnet Mask . . Lease Obtained. Lease Expires . Default Gateway

. . . .

. . . .

. . . .

. . . .

: : : :

255.255.255.0 Friday, September 6, 2019 11:08:36 AM Saturday, September 7, 2019 11:08:36 AM 192.168.1.1

. . . .

. . . .

. . . .

. . . .

. . . .



When using the ipconfig /all command, notice that MAC addresses are referred to as physical addresses. Reading the MAC address from left to right, the first six hex digits refer to the vendor (manufacturer) of this device. These first six hex digits (3 bytes) are also known as the organizationally unique identifier (OUI). This 3-byte code is assigned to the vendor by the IEEE organization. To find the manufacturer, use the keywords IEEE OUI standards to find an OUI lookup tool on the internet or navigate to http://standards-oui.ieee.org/oui.txt to find the registered OUI vendor codes. The last six digits are the NIC serial number assigned by the manufacturer. a. Open a command prompt on PC-A and PC-B and type ipconfig /all. What are the LAN connection adapter’s physical addresses?

PC-A MAC Address: 00D0.D317.C101 What is the OUI portion of the MAC address for PC-A? the potion is 00D0.D3 What is the serial number portion of the MAC address for PC-A?17.C101

PC-B MAC Address: 00E0.8FA6.8EEE What is the OUI portion of the MAC address for PC-B? 00E0.8F What is the serial number portion of the MAC address for PC-B? A6.8EEE Find the name of the vendor that manufactured these NICs. Cisco Systems.inc

Step 2: Examine the MAC addresses for the switches S1 and S2. You can use a variety of commands to display MAC addresses on the switch. a. Console into the switches and use the show interfaces command for vlan 1 and port Fa0/6 or Fa0/18 to display MAC address information. A sample is shown below. Use the output generated by your switch to answer the questions. S1# show interfaces vlan 1 Vlan1 is up, line protocol is up Hardware is EtherSVI, address is 001b.0c6d.8f40 (bia 001b.0c6d.8f40) Internet address is 192.168.1.11/24 MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set

S2# show interface f0/18

FastEthernet0/18 is up, line protocol is up (connected) Hardware is Fast Ethernet, address is 0025.83e6.9081 (bia 0025.83e6.9081) MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,

On the second line of command output, what are the hardware addresses (or burned-in address [bia])? S1 vlan1 MAC Address: 0090.2150.c9ec S2 Fast Ethernet 0/18 MAC Address: 00d0.ba0a.c712 b. Another way to display the MAC address on the switch is to use the show arp command. Use the show arp command to display MAC address information. This command maps the Layer 2 address to its corresponding Layer 3 address. Use output generated by your switch to answer the questions. What Layer 2 addresses are displayed on S1? 192.168.1.11 What Layer 3 addresses are displayed on S1? 192.168.1.12

Step 3: Display the switch MAC address table. Issue the show mac address-table command on S1. Use output generated by your switch to answer the questions. Instructor Note: The show mac address-table command can vary based on the model switch you are using. For example, the syntax on some switches is show mac-address-table. S1# show mac address-table

Even though there has been no network communication initiated across the network (i.e., no use of ping), it is possible that the switch has learned MAC addresses from its connection to the PCs and the other switch. Are there any MAC addresses recorded in the MAC address table? Yes What MAC addresses are recorded in the table? To which switch ports are they mapped and to which devices do they belong? Ignore MAC addresses that are mapped to the CPU. Addresses are 00d0.ba0a.c701, switch port is fa0/1 If you had not previously recorded MAC addresses of network devices in Step 1, how could you tell which devices the MAC addresses belong to, using only the output from the show mac address-table command? Does it work in all scenarios?

Step 4: Clear the S2 MAC address table and display the MAC address table again. a. In privileged EXEC mode, type the clear mac address-table dynamic command and press Enter. S2# clear mac address-table dynamic

b. Quickly type the show mac address-table command again. Does the MAC address table have any addresses in it for VLAN 1? Are there other MAC addresses listed? No, there’s no addresses, and no other MAC addresses Wait 10 seconds, type the show mac address-table command, and press Enter. Are there new addresses in the MAC address table? Yes, there are new addresses in the table.

From PC-B, ping the devices on the network and observe the switch MAC address table. c.

From PC-B, open a command prompt and type arp -a. Not including multicast or broadcast addresses, how many device IP-to-MAC address pairs have been learned by ARP? Two addresses have been learned

d. From the PC-B command prompt, ping PC-A, S1, and S2. Did all devices have successful replies? If not, check your cabling and IP configurations.

Yes, all successful. e. From a console connection to S2, enter the show mac address-table command. Has the switch added additional MAC addresses to the MAC address table? If so, which addresses and devices?

Yes, the addresses are 00d0.d317.c10100 and 00e0.8fa6.8eee, devices are fa0/1 and fa0/18 From PC-B, open a command prompt and retype arp -a. Does the PC-B ARP cache have additional entries for all network devices that were sent pings? If so, which do they devices do they correspond with?

Yes, the devices are S2 and PCA

Reflection 1. Can you have broadcasts at the Layer 2 level? If so, what would the MAC address be? You can have broadcasts at Layer 2. the address would be ff.ff.ff.ff.ff.ff 2. Why would you need to know the MAC address of a device? In a large network, it may be easier to pinpoint location and identity of a device by its MAC address instead of its IP address. Security measures can be applied at Layer 2, so MAC addresses is needed. 3. On Ethernet networks, data is delivered to devices by their MAC addresses. For this to happen, switches and PCs dynamically build ARP caches and MAC address tables. With only a few computers on the network this process seems fairly easy. What might be some of the challenges on larger networks?

Part 4: Use the IOS show arp Command The Cisco IOS on routers and switches can also display the ARP cache on routers and switches with the show arp or show ip arp command.

Step 1: Display ARP entries on switch S1. S1# show ip arp Protocol Internet Internet Internet S1#

Address 192.168.1.2 192.168.1.3 192.168.1.11

Age (min) 8 8 -

Hardware Addr 0050.56be.f6db 0050.56be.768c 0cd9.96e8.8a40

Type ARPA ARPA ARPA

Interface Vlan1 Vlan1 Vlan1

Step 2: Add ARP entries on switch S1. By pinging other devices, ARP entries can also be added to the ARP table of the switch. a. From switch S1, ping switch S2. S1# ping 192.168.1.12 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.1.12, timeout is 2 seconds: .!!!! Success rate is 80 percent (4/5), round-trip min/avg/max = 1/2/8 ms

b. Verify that the ARP entry for switch S2 has been added to ARP table of S1. S1# show ip arp Protocol Internet Internet

Address 192.168.1.2 192.168.1.3

Internet

192.168.1.11

Age (min) 11 11 -

Hardware Addr 0050.56be.f6db 0050.56be.768c

Type ARPA ARPA

Interface Vlan1 Vlan1

0cd9.96e8.8a40

ARPA

Vlan1

Internet S1#

192.168.1.12

2

0cd9.96d2.4040

ARPA

Vlan1...


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