Explanation:
You should use SSH to connect to the devices for management. You should also require an encrypted password for VTY access. Using Telnet for remote management transmits all information, including the username and passwords, in clear text. Using an encrypted password for VTY access ensures that the password cannot be read either in transit or in the configuration file.

Passwords used for access to the console, aux, or VTY connections can be encrypted if desired. When passwords are created with the enable command, the password is saved in clear text. When the enable secret command is used, however the password will be encrypted.

If both types of password are configured for a particular connection type, the system will ignore the enable password and require the enable secret password. For example, if the set of commands shown below were executed, both types of password will be created for console access, but the system will require the password crisco rather than cisco. Also make note that neither of those passwords will required for VTY access. That password is sicso, which is the password configured after accessing the line VTY interface configuration prompt.

Router(config)# enable secret crisco
Router(config)# enable password cisco
Router(config)# line vty 0 4
Router(config-line)# password sisco

Although it is possible to encrypt the password in the configuration files, it is not possible to encrypt the rest of the files.

You should not disable the encryption of the passwords in the configuration files. Password encryption is a good security measure to take, and sloppy password management should not be a reason to change this practice.

You should not disable the VTY ports on the devices. This would certainly enhance security, but it would prevent you from managing the devices remotely .

Explanation:
It will find the response time to resolve the DNS name cow.cisco.com. Domain Name System (DNS) response time is computed by calculating the difference between the time taken to send a DNS request and the time a reply is received. The Cisco IOS IP SLAs DNS operation queries for an IP address if the user specifies a hostname, or queries for a hostname if the user specifies an IP address.

It will not find the response time to connect to the DNS server at 10.52.128.30. That is the IP address of the DNS server being used for the operation (10.52.128.30). However, it will measure the response time to resolve the DNS name cow.cisco.com.

It will not start in one minute. It will start immediately, as indicated by the start-time now parameter.

It will not gather data for one minute. The numeral 1 in the first line refers to the IP SLA number, and the numeral 1 in the last line refers to the IP SLA number to be scheduled.

Explanation:
Despite the inclusion of the command aggregate-address 192.168.5.0 255.255.252.0, all subnets of the aggregate route will also be placed in the routing updates because of the omission of the summary-only keyword. Therefore, 192.168.5.4/29, 172.16.5.0/16, 192.168.6.0/24 and 192.168.7.0/24 will be present.

Had the following command been executed, the subnet addresses would not appear in the routing table of the router at 172.16.5.2:

Router5(config-router)# aggregate-address 192.168.5.0 255.255.252.0 summary-only

Therefore, both the aggregate address and all of the 192.168.0.0 subnets will be in the routing table.

The 172.16.5.0/24 network will be in the routing table of the router at 172.160.5.1 because it is directly connected.

Explanation:
The show vlans command would NOT be useful for discovering the problem. When troubleshooting a problem with Hot Standby Router Protocol (HSRP), the show vlans command will yield no useful information.

All three of the remaining commands will be useful in discovering information. Each is shown below with an example of its application to troubleshooting. Example A: show running-configuration
Router B is not taking over as the active device for VLAN 101’s HSRP group when the Fa0/1 interface on Router A fails. Below is a partial output of show run for both routers with the output focused on the section concerning VLAN 101’s configuration on each.

The above output displays the source of the problem. Router A has a decrement value of 5 configured for Fa0/1, as shown on the last line of the output after the specification of Fastethernet 0/1. This means that when its Fa0/1 interface goes down, Router A will subtract 5 from its priority for the VLAN 101 group, lowering it to
175. This is still higher than the priority of Router B, which is 170. Therefore, the solution is to change the decrement value for Router A to at least 11. When the interface goes down, Router A’s priority will be decremented to 169, allowing Router B to take the role as active for the HSRP group in VLAN 101.

Example B: show standby brief

Router C is not taking over as the active device for VLAN 102’s HSRP group when the Fa0/1 interface on Router D fails. Below is a partial output of show standby brief for both routers C and D, with the output focused on the section concerning VLAN 102’s configuration on each.

Explanation:
The clock rate is set on the Data Circuit-terminating Equipment (DCE) device. DCE is also known as Data Communications Equipment.

DCE terminates a physical WAN connection and provides clocking and synchronization of a connection between two locations and connects to a DTE. The DCE category includes equipment such as CSU/DSUs and modems. If you were connecting a router to a WAN link, the router would be the DTE end and would be connected to a CSU/DSU or a modem. Either of these devices would provide the clocking.

DTE is an end-user device, such as a router or a PC that connects to the WAN via the DCE device.

Other options are incorrect. By default, no clock rate is configured, but can be set on a DCE device by using the clock rate [bps] command.

Explanation:
IPv6 addresses are divided into eight 16-bit groups, a double colon (::) can only be used once in an IPv6 address, and groups with a value of 0 can be represented with a single 0 in an IPv6 address.

The following statements are also true regarding IPv6 address:
– IPv6 addresses are 128 bits in length.
– Eight 16-bit groups are divided by a colon (:).
– Multiple consecutive groups of 16-bit 0s can be represented with double colon (::)
– ( only once) Double colons (::) represent only 0s.
– Leading zeros can be omitted in an IPv6 address.

The option stating that IPv6 addresses are 196 bits in length is incorrect. IPv6 addresses are 128 bits in length.

The option stating that leading zeros cannot be omitted in an IPv6 address is incorrect. Leading zeros can be omitted in an IPv6 address.

Explanation:
The VLAN database of the new switch will overwrite the VLAN databases of the production switches because it is operating in server mode and has a higher VLAN configuration revision number. The VLAN Trunking Protocol (VTP) is used to synchronize VLANs between different switches. The VTP configuration revision number is used to determine which VTP switch has the most current version of the VLAN database, and is incremented whenever a VLAN change is made on a VTP server switch.

Explanation:
The command output excerpt indicates that the link is not functional due to a Data Link layer (or “line protocol”) issue, while the Physical layer (Layer 1) is operational. The first (left) column indicates the Physical layer state of the interface, while the second (right) column indicates the Data Link layer state of the interface.

The link is not fully functional. Were it fully functional, the command output would be:

Ethernet0/0 is up, line protocol is up

The link is not suffering a Physical layer issue or a combination of Physical layer and Layer 2 (Data Link) layer issues. Were either the case, the output would be:

Ethernet 0/0 is down, line protocol is down

Note: if a Physical layer issue exists, there will also be a Data Link issue, since the Data Link layer depends on the Physical layer to provide connectivity.

Explanation:
After typing the Ctrl-Shift-6 sequence, you can tap the x key and return to the previous session, which in this case was the session with the router. Below is the full sequence of commands described in this item:

Router1#telnet 192.168.3.3 Tying 192.168.3.3..Open User Access Verification Password:
Switch2><Ctrl-Shift-6>x Router1#

When you desired to return to the session with the switch, you would use the resume command as shown below:

Router1#resume Switch>

Neither the suspend nor the <Ctrl-Shift-6>shift commands are valid commands.