4.4.8 Packet Tracer – Configure Secure Passwords and SSH Answers
Topology
4.4.8 Packet Tracer – Configure Secure Passwords and SSH
Addressing Table
| Device | Interface | IP Address | Subnet Mask | Default Gateway |
|---|---|---|---|---|
| RTA | G0/0/0 | 172.16.1.1 | 255.255.255.0 | N/A |
| PCA | NIC | 172.16.1.10 | 255.255.255.0 | 172.16.1.1 |
| SW1 | VLAN 1 | 172.16.1.2 | 255.255.255.0 | 172.16.1.1 |
Scenario
The network administrator has asked you to prepare RTA and SW1 for deployment. Before they can be connected to the network, security measures must be enabled.
Intructions
Part 1: Configure Basic Security on the Router
a. Configure IP addressing on PCA according to the Addressing Table.
Go to PCA > Desktop tab > IP Configuration
b. Console into RTA from the Terminal on PCA.
Go to PCA > Desktop tab > Terminal > OK
c. Configure the hostname as RTA.
Router(config)#hostname RTA
d. Configure IP addressing on RTA and enable the interface.
RTA(config)#interface GigabitEthernet0/0/0 RTA(config-if)#ip address 172.16.1.1 255.255.255.0 RTA(config-if)#no shutdown
e. Encrypt all plaintext passwords.
RTA(config)# service password-encryption
f. Set the minimum password length to 10.
RTA(config)# security passwords min-length 10
g. Set a strong secret password of your choosing.
RTA(config-if)#enable secret any_password
Note: Choose a password that you will remember, or you will need to reset the activity if you are locked out of the device.
h. Disable DNS lookup.
RTA(config)# no ip domain-lookup
i. Set the domain name to netsec.com (case-sensitive for scoring in PT).
RTA(config)# ip domain-name netsec.com
j. Create a user of your choosing with a strong encrypted password.
RTA(config)# username any_user secret any_password
k. Generate 1024-bit RSA keys.
Note: In Packet Tracer, enter the crypto key generate rsa command and press Enter to continue.
RTA(config)# crypto key generate rsa The name for the keys will be: RTA.netsec.com Choose the size of the key modulus in the range of 360 to 2048 for your General Purpose Keys. Choosing a key modulus greater than 512 may take a few minutes. How many bits in the modulus [512]: 1024
l. Block anyone for three minutes who fails to log in after four attempts within a two-minute period.
RTA(config)# login block-for 180 attempts 4 within 120
m. Configure all VTY lines for SSH access and use the local user profiles for authentication.
RTA(config)# line vty 0 4 RTA(config-line)# transport input ssh RTA(config-line)# login local
n. Set the EXEC mode timeout to 6 minutes on the VTY lines.
RTA(config-line)# exec-timeout 6
o. Save the configuration to NVRAM.
RTA#copy running-config startup-config
p. Access the command prompt on the desktop of PCA to establish an SSH connection to RTA.
Go to PCA > Desktop tab > Command Prompt
C:\>ssh -l any_user 172.16.1.1 Password: any_password RTA>
Part 2: Configure Basic Security on the Switch
Configure switch SW1 with corresponding security measures. Refer to the configuration steps on the router if you need additional assistance.
a. Console into SW1 from the Terminal on PCA.
On the RTA side, click the black circle on the Console cable > Click to SW1 > Select Console
Go to PCA > Desktop tab > Terminal > OK
b. Configure the hostname as SW1.
Switch(config)#hostname SW1
c. Configure IP addressing on SW1 VLAN1 and enable the interface.
SW1(config-if-range)#interface Vlan1 SW1(config-if)#ip address 172.16.1.2 255.255.255.0 SW1(config-if)#no shutdown
d. Configure the default gateway address.
SW1(config-if)#ip default-gateway 172.16.1.1
e. Disable all unused switch ports.
Note: On a switch it is a good security practice to disable unused ports. One method of doing this is to simply shut down each port with the ‘shutdown’ command. This would require accessing each port individually. There is a shortcut method for making modifications to several ports at once by using the interface range command. On SW1 all ports except FastEthernet0/1 and GigabitEthernet0/1 can be shutdown with the following command:
SW1(config)# interface range F0/2-24, G0/2 SW1(config-if-range)# shutdown %LINK-5-CHANGED: Interface FastEthernet0/2, changed state to administratively down %LINK-5-CHANGED: Interface FastEthernet0/3, changed state to administratively down <Output omitted> %LINK-5-CHANGED: Interface FastEthernet0/24, changed state to administratively down %LINK-5-CHANGED: Interface GigabitEthernet0/2, changed state to administratively down
The command used the port range of 2-24 for the FastEthernet ports and then a single port range of GigabitEthernet0/2.
f. Encrypt all plaintext passwords.
SW1(config)#service password-encryption
g. Set a strong secret password of your choosing.
SW1(config)#enable secret any_password
h. Disable DNS lookup.
SW1(config)#no ip domain-lookup
i. Set the domain name to netsec.com (case-sensitive for scoring in PT).
SW1(config)#ip domain-name netsec.com
j. Create a user of your choosing with a strong encrypted password.
SW1(config)#username my_user secret my_password
k. Generate 1024-bit RSA keys.
SW1(config)#crypto key generate rsa The name for the keys will be: SW1.netsec.com Choose the size of the key modulus in the range of 360 to 4096 for your General Purpose Keys. Choosing a key modulus greater than 512 may take a few minutes. How many bits in the modulus [512]: 1024
l. Configure all VTY lines for SSH access and use the local user profiles for authentication.
SW1(config)#line vty 0 15 SW1(config-line)#transport input ssh SW1(config-line)#login local
m. Set the EXEC mode timeout to 6 minutes on all VTY lines.
SW1(config)#line vty 0 15 SW1(config-line)#exec-timeout 6 0
n. Save the configuration to NVRAM.
SW1#copy running-config startup-config
Answers Script:
RTA
enable configure terminal hostname RTA interface GigabitEthernet0/0/0 ip address 172.16.1.1 255.255.255.0 no shutdown service password-encryption security passwords min-length 10 enable secret any_password no ip domain-lookup ip domain-name netsec.com username any_user secret any_password crypto key generate rsa 1024 login block-for 180 attempts 4 within 120 line vty 0 4 transport input ssh login local exec-timeout 6 end copy running-config startup-config
SW1
enable configure terminal hostname SW1 interface Vlan1 ip address 172.16.1.2 255.255.255.0 no shutdown ip default-gateway 172.16.1.1 interface range F0/2-24, G0/2 shutdown service password-encryption enable secret any_password no ip domain-lookup ip domain-name netsec.com username my_user secret my_password crypto key generate rsa 1024 line vty 0 15 transport input ssh login local exec-timeout 6 0 end copy running-config startup-config
