24.1.5 Lab – Implement SPAN Technologies Answers

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Lab – Implement SPAN Technologies (Answers Version)

Answers Note: Red font color or gray highlights indicate text that appears in the instructor copy only.

Topology

Addressing Table

Objectives

Part 1: Build the Network and Configure Basic Device Settings and Interface Addressing

Part 2: Configure and Verify Local SPAN

Part 3: Configure and Verify RSPAN

Background / Scenario

The Switch Port Analyzer (SPAN) feature allows you to instruct a switch to send copies of packets seen on one port, multiple ports, or an entire VLAN, to another port on the same switch. The Remote SPAN (RSPAN) feature takes the SPAN feature beyond a single switch to a network, allowing you to remotely capture traffic on different switches in the network. This is extremely useful in campus networks where a sniffer may not be located at the desired traffic capture point. In addition, this allows you to permanently place a sniffer in the campus network to SPAN traffic as necessary or when troubleshooting situations arise.

Note: This lab is an exercise in configuring options available for SPAN and does not necessarily reflect network troubleshooting best practices.

Answers Note: This lab may not work as intended if you are using NETLAB with a control switch.

Note: The switches used in the CCNP hands-on labs are Cisco Catalyst 3650s with Cisco IOS XE Release 16.9.4 (universalk9 image) and Cisco Catalyst 2960s with Cisco IOS Release 15.2(2) (lanbasek9 image). Other switches and Cisco IOS versions can be used. Depending on the model and Cisco IOS version, the commands available and the output produced might vary from what is shown in the labs.

Note: Make sure that the switches have been erased and have no startup configurations. If you are unsure, contact your instructor.

Note: The default Switch Database Manager (SDM) template on a Catalyst 2960 does not support IPv6. You must change the default SDM template to the dual-ipv4-and-ipv6 default template using the sdm prefer dual-ipv4-and-ipv6 default global configuration command. Changing the template will require a reboot.

Answers Note: Refer to the Answers Lab Manual for the procedures to initialize and reload devices.

Required Resources

• 1 Switch (Cisco 3650 with Cisco IOS XE Release 16.9.4 universal image or comparable)
• 1 Switch (Cisco 2960 with Cisco IOS Release 15.2(2) lanbasek9 image or comparable)
• 4 PCs (Choice of operating system with terminal emulation program and with a packet capture utility)
• Console cables to configure the Cisco IOS devices via the console ports
• Ethernet cables as shown in the topology

Part 1:Build the Network and Configure Basic Device Settings and Interface Addressing

In Part 1, you will set up the network topology and configure basic settings and interface addressing on switches.

Step 1:Cable the network as shown in the topology.

Attach the devices as shown in the topology diagram, and cable as necessary.

Step 2:Configure basic settings for each device.

1. Console into each device, enter global configuration mode, and apply the basic settings. The startup configurations for each device are provided below.

Open configuration window

Switch D1

config t

hostname D1

no ip domain lookup

ip routing

ipv6 unicast-routing

banner motd # D1, Implement SPAN Technologies #

line con 0

exec-timeout 0 0

logging synchronous

exit

line vty 0 4

privilege level 15

exec-timeout 0 0

password cisco123

login

exit

vlan 2

name SECOND_VLAN

exit

vlan 3

name THIRD_VLAN

exit

interface vlan 1

ip address 192.168.1.1 255.255.255.0

ipv6 address fe80::d1:1 link-local

ipv6 address 2001:db8:acad:1000::1/64

no shutdown

exit

interface vlan 2

ip address 192.168.2.1 255.255.255.0

ipv6 address fe80::d1:2 link-local

ipv6 address 2001:db8:acad:2000::1/64

no shutdown

exit

interface vlan 3

ip address 192.168.3.1 255.255.255.0

ipv6 address fe80::d1:3 link-local

ipv6 address 2001:db8:acad:3000::1/64

no shutdown

exit

interface range g1/0/23

spanning-tree portfast

switchport mode access

no shutdown

exit

interface range g1/0/24

spanning-tree portfast

switchport mode access

switchport access vlan 2

no shutdown

exit

interface range g1/0/5-6

switchport mode trunk

channel-group 1 mode active

no shutdown

exit

interface range g1/0/1-4, g1/0/7-22, g1/1/1-4

shutdown

exit

ip dhcp pool SECOND_VLAN_POOL

network 192.168.2.0 255.255.255.0

default-router 192.168.2.1

exit

ip dhcp pool THIRD_VLAN_POOL

network 192.168.3.0 255.255.255.0

default-router 192.168.3.1

exit

end

Switch A1

config t

hostname A1

no ip domain lookup

ipv6 unicast-routing

banner motd # A1, Implement SPAN Technologies #

line con 0

exec-timeout 0 0

logging synchronous

exit

line vty 0 4

privilege level 15

exec-timeout 0 0

password cisco123

login

exit

vlan 2

name SECOND_VLAN

exit

vlan 3

name THIRD_VLAN

exit

interface vlan 1

ip address 192.168.1.3 255.255.255.0

ipv6 address fe80::a1:1 link-local

ipv6 address 2001:db8:acad:1000::3/64

no shutdown

exit

interface range f0/1-2

switchport mode trunk

channel-group 1 mode active

no shutdown

exit

interface range f0/23 – 24

switchport mode access

switchport access vlan 3

spanning-tree portfast

no shutdown

exit

interface range f0/3-22, g0/1-2

shutdown

exit

end

2. Set the clock on each device to UTC time.
3. Save the running configuration to startup-config.
4. Configure IPv4 and IPv6 addresses on all hosts as shown in the addressing table.
5. Verify that the PCs can ping their default gateways and each other.

Close configuration window

Part 2:Configure and Verify Local SPAN

In this part you will configure and verify a local SPAN on D1, configuring it so that PC1 is able to capture traffic from PC2, even though it is in a different VLAN.

Step 1:Configure Local SPAN.

1. Create a Local SPAN session with a source of g1/0/24 and a destination of g1/0/23. The monitor session number is locally significant only, so you can use any number IOS XE allows you to. Note that there is a limit to the number of sessions that can run simultaneously, and that the SPAN can consume significant resources.

Open configuration window

D1(config)# monitor session 1 source interface g1/0/24

D1(config)# monitor session 1 destination interface g1/0/23

2. Verify the configuration by issuing the show monitor session # or show monitor session local command.

D1# show monitor session local

Session 1

———

Type: Local Session

Source Ports:

Both: Gi1/0/24

Destination Ports: Gi1/0/23

Encapsulation: Native

Ingress: Disabled

Close configuration window

Step 2:Verify that the SPAN is operational.

1. On PC 1, open Wireshark and start capturing on the Ethernet interface. Add the capture filter icmp.
2. On PC 2, ping 192.168.1.1. Send 3 packets of 300 bytes.

On a Windows PC, the command is ping -n 3 -l 300 192.168.1.1

On a Linux PC, the command is ping -s 300 -c 3 192.168.1.1

3. On PC 1, stop the Wireshark capture and examine the output.
4. Remove the monitor session using the no monitor session 1 command.

Part 3:Configure and Verify RSPAN

In this part, you will configure and verify a Remote SPAN (RSPAN). RSPAN allows the source and destination ports to be on different switches. For this to work, it uses a VLAN configured only for remote–span functionality. The source port then places the transmitted or received data onto the remote–span VLAN. The remote–span VLAN is carried across trunks. The receiving switch takes the data sourced from the remote-span VLAN and sends it to the destination port that is running the protocol analyzer.

VLAN 500 will be created on D1 and A1 to be used as the remote–span VLAN. PC 1 will again take on the capture role, this time it will be interested in traffic coming from VLAN 2 on Switch A1.

Step 1:Configure RSPAN VLAN.

1. Create the RSPAN VLAN on D1 and A1 using the vlan 500 command from global configuration mode.

Open configuration window

D1# config t

Enter configuration commands, one per line.End with CNTL/Z.

D1(config)# vlan 500

D1(config-vlan)# name Remote_SPAN

D1(config-vlan)# remote-span

D1(config-vlan)# exit

2. Use the show vlan remote-span command to verify VLAN 500 is configured correctly and is designated as the remote-span vlan.Use the show interface trunk command to ensure the RSPAN VLAN is allowed on the trunks. The RSPAN VLAN should not be a DATA VLAN. Its purpose is strictly for carrying the monitored traffic across trunk links from one switch to another.

D1# show vlan remote-span

Remote SPAN VLANs

—————————————————————————–

500

D1# show interface trunk

PortModeEncapsulationStatusNative vlan

Po1on802.1qtrunking1

PortVlans allowed on trunk

Po11-4094

PortVlans allowed and active in management domain

Po11-3,500

PortVlans in spanning tree forwarding state and not pruned

Po11-3,500

3. Now configure the monitor session on A1 with a source interface of vlan 2 and a destination of remote vlan 500. Because the captured traffic must traverse the local switch to a remote switch, we must use the remote VLAN as the destination.

A1(config)# monitor session 2 source vlan 3

A1(config)# monitor session 2 destination remote vlan 500

%Note: ingoring the reflector port configuration

Note: The ignoring the reflector port message is an artifact of an older OS and can be safely ignored.

Close configuration window

4. Verify the configuration using the show monitor session 2 command.

Open configuration window

A1# show monitor session 2

Session 2

———

Type: Remote Source Session

Source VLANs:

Both: 3

Dest RSPAN VLAN: 500

Close configuration window

5. Move to the D1 switch and configure it to collect the desired traffic. The source port on D1 will be the remote-span vlan 500 and the destination port will be the client connected to G1/0/23.

Open configuration window

D1(config)# monitor session 2 source remote vlan 500

D1(config)# monitor session 2 destination interface g1/0/23

Note that the session numbers do not have to match at either end of the session.

6. Verify the configuration using the show monitor session 2 command on D1.

D1# show monitor session 2

Session 2

———

Type: Remote Destination Session

Source RSPAN VLAN: 500

Destination Ports: Gi1/0/23

Encapsulation: Native

Ingress: Disabled

Close configuration window

Step 2:Verify that the SPAN is operational.

1. On PC 1, open Wireshark and start capturing on the Ethernet interface.
2. On PC3 and PC4 (the hosts on A1), ping 192.168.1.1. Send 3 packets of 300 bytes.

On a Windows PC, the command is ping -n 3 -l 300 192.168.1.1

On a Linux PC, the command is ping -s 300 -c 3 192.168.1.1

3. On PC 1, stop the Wireshark capture and examine the output. You should see pings sourced from PC3 and PC4, along with responses to those pings.
4. Remove the monitor session using the no monitor session 2 command on A1 and D1.

End of document

Device Configs – Final

Switch D1

D1# show run

Building configuration…

Current configuration : 9628 bytes

!

version 16.9

no service pad

service timestamps debug datetime msec

service timestamps log datetime msec

! Call-home is enabled by Smart-Licensing.

service call-home

no platform punt-keepalive disable-kernel-core

!

hostname D1

!

vrf definition Mgmt-vrf

!

address-family ipv4

exit-address-family

!

address-family ipv6

exit-address-family

!

no aaa new-model

switch 1 provision ws-c3650-24ts

!

ip routing

!

no ip domain lookup

!

ip dhcp pool SECOND_VLAN_POOL

network 192.168.2.0 255.255.255.0

default-router 192.168.2.1

!

ip dhcp pool THIRD_VLAN_POOL

network 192.168.3.0 255.255.255.0

default-router 192.168.3.1

!

login on-success log

ipv6 unicast-routing

!

license boot level ipservicesk9

!

diagnostic bootup level minimal

!

spanning-tree mode rapid-pvst

spanning-tree extend system-id

!

redundancy

mode sso

!

transceiver type all

monitoring

!

class-map match-any system-cpp-police-topology-control

description Topology control

class-map match-any system-cpp-police-sw-forward

description Sw forwarding, L2 LVX data, LOGGING

class-map match-any system-cpp-default

description Inter FED, EWLC control, EWLC data

class-map match-any system-cpp-police-sys-data

description Learning cache ovfl, High Rate App, Exception, EGR Exception, NFL SAMPLED DATA, RPF Failed

class-map match-any system-cpp-police-punt-webauth

description Punt Webauth

class-map match-any system-cpp-police-l2lvx-control

description L2 LVX control packets

class-map match-any system-cpp-police-forus

description Forus Address resolution and Forus traffic

class-map match-any system-cpp-police-multicast-end-station

description MCAST END STATION

class-map match-any system-cpp-police-multicast

description Transit Traffic and MCAST Data

class-map match-any system-cpp-police-l2-control

description L2 control

class-map match-any system-cpp-police-dot1x-auth

description DOT1X Auth

class-map match-any system-cpp-police-data

description ICMP redirect, ICMP_GEN and BROADCAST

class-map match-any system-cpp-police-stackwise-virt-control

description Stackwise Virtual

class-map match-any non-client-nrt-class

class-map match-any system-cpp-police-routing-control

description Routing control and Low Latency

class-map match-any system-cpp-police-protocol-snooping

description Protocol snooping

class-map match-any system-cpp-police-dhcp-snooping

description DHCP snooping

class-map match-any system-cpp-police-system-critical

description System Critical and Gold Pkt

!

policy-map system-cpp-policy

!

interface Port-channel1

switchport mode trunk

!

interface GigabitEthernet0/0

vrf forwarding Mgmt-vrf

no ip address

shutdown

negotiation auto

!

interface GigabitEthernet1/0/1

shutdown

!

interface GigabitEthernet1/0/2

shutdown

!

interface GigabitEthernet1/0/3

shutdown

!

interface GigabitEthernet1/0/4

shutdown

!

interface GigabitEthernet1/0/5

switchport mode trunk

channel-group 1 mode active

!

interface GigabitEthernet1/0/6

switchport mode trunk

channel-group 1 mode active

!

interface GigabitEthernet1/0/7

shutdown

!

interface GigabitEthernet1/0/8

shutdown

!

interface GigabitEthernet1/0/9

shutdown

!

interface GigabitEthernet1/0/10

shutdown

!

interface GigabitEthernet1/0/11

shutdown

!

interface GigabitEthernet1/0/12

shutdown

!

interface GigabitEthernet1/0/13

shutdown

!

interface GigabitEthernet1/0/14

shutdown

!

interface GigabitEthernet1/0/15

shutdown

!

interface GigabitEthernet1/0/16

shutdown

!

interface GigabitEthernet1/0/17

shutdown

!

interface GigabitEthernet1/0/18

shutdown

!

interface GigabitEthernet1/0/19

shutdown

!

interface GigabitEthernet1/0/20

shutdown

!

interface GigabitEthernet1/0/21

shutdown

!

interface GigabitEthernet1/0/22

shutdown

!

interface GigabitEthernet1/0/23

switchport mode access

spanning-tree portfast

!

interface GigabitEthernet1/0/24

switchport access vlan 2

switchport mode access

spanning-tree portfast

!

interface GigabitEthernet1/1/1

shutdown

!

interface GigabitEthernet1/1/2

shutdown

!

interface GigabitEthernet1/1/3

shutdown

!

interface GigabitEthernet1/1/4

shutdown

!

interface Vlan1

ip address 192.168.1.1 255.255.255.0

ipv6 address FE80::D1:1 link-local

ipv6 address 2001:DB8:ACAD:1000::1/64

!

interface Vlan2

ip address 192.168.2.1 255.255.255.0

ipv6 address FE80::D1:2 link-local

ipv6 address 2001:DB8:ACAD:2000::1/64

!

interface Vlan3

ip address 192.168.3.1 255.255.255.0

ipv6 address FE80::D1:3 link-local

ipv6 address 2001:DB8:ACAD:3000::1/64

!

ip forward-protocol nd

ip http server

ip http authentication local

ip http secure-server

!

!

control-plane

service-policy input system-cpp-policy

!

banner motd ^C D1, Implement SPAN Technologies ^C

!

line con 0

exec-timeout 0 0

logging synchronous

stopbits 1

line aux 0

stopbits 1

line vty 0 4

exec-timeout 0 0

privilege level 15

password cisco123

login

line vty 5 15

login

!

end

Switch A1

A1# show run

Building configuration…

Current configuration : 3698 bytes

!

version 15.2

no service pad

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname A1

!

boot-start-marker

boot-end-marker

!

no aaa new-model

system mtu routing 1500

!

no ip domain-lookup

ipv6 unicast-routing

!

spanning-tree mode pvst

spanning-tree extend system-id

!

vlan internal allocation policy ascending

!

interface Port-channel1

switchport mode trunk

!

interface FastEthernet0/1

switchport mode trunk

channel-group 1 mode active

!

interface FastEthernet0/2

switchport mode trunk

channel-group 1 mode active

!

interface FastEthernet0/3

shutdown

!

interface FastEthernet0/4

shutdown

!

interface FastEthernet0/5

shutdown

!

interface FastEthernet0/6

shutdown

!

interface FastEthernet0/7

shutdown

!

interface FastEthernet0/8

shutdown

!

interface FastEthernet0/9

shutdown

!

interface FastEthernet0/10

shutdown

!

interface FastEthernet0/11

shutdown

!

interface FastEthernet0/12

shutdown

!

interface FastEthernet0/13

shutdown

!

interface FastEthernet0/14

shutdown

!

interface FastEthernet0/15

shutdown

!

interface FastEthernet0/16

shutdown

!

interface FastEthernet0/17

shutdown

!

interface FastEthernet0/18

shutdown

!

interface FastEthernet0/19

shutdown

!

interface FastEthernet0/20

shutdown

!

interface FastEthernet0/21

shutdown

!

interface FastEthernet0/22

shutdown

!

interface FastEthernet0/23

switchport access vlan 3

switchport mode access

spanning-tree portfast

!

interface FastEthernet0/24

switchport access vlan 3

switchport mode access

spanning-tree portfast

!

interface GigabitEthernet0/1

shutdown

!

interface GigabitEthernet0/2

shutdown

!

interface Vlan1

ip address 192.168.1.3 255.255.255.0

ipv6 address FE80::A1:1 link-local

ipv6 address 2001:DB8:ACAD:1000::3/64

!

ip http server

ip http secure-server

!

banner motd ^C A1, Implement SPAN Technologies ^C

!

line con 0

exec-timeout 0 0

logging synchronous

line vty 0 4

exec-timeout 0 0

privilege level 15

password cisco123

login

line vty 5 15

login

!

end

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