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The source of the increased CPU utilization will have two sources. First is the process switching of each packet that matches the ACE, which is a slower switching method than CEF switching. The second is the generation and transmission of the log messages. Both effects can be mitigated by adjusting the logging interval and the message interval.

The CPU utilization does NOT increase from the incrementing of the match counter every 60 seconds. The match counter increments every 5 minutes by default.

The CPU utilization does NOT increase from the CEF switching of packets that match the ACE. Those packets will be process switched, which is a much slower process than CEF switching.

Objective:
Infrastructure Security Sub-Objective:
Configure and verify router security features

References:
Understanding Access Control List Logging
Cisco > Cisco IOS Security Command Commands D to L > ip access-list log-update Cisco > Cisco IOS
Broadband Access Aggregation and DSL Command Reference > logging rate-limit

Note: By default Static Router AD value-1 hence ip route 0.0.0.0. 0.0.0.0. 1.1.1.1 track 1 means AD-1 which must be less than of back up route AD.
Define the backup route to use when the tracked object is unavailable.
!--- The administrative distance of the backup route must be greater than !--- the administrative distance of the tracked route.
!--- If the primary gateway is unreachable, that route is removed
!--- and the backup route is installed in the routing table
!--- instead of the tracked route.
References:
https://www.cisco.com/c/en/us/support/docs/ip/ip-routing/200785-ISP-Failover-with-default-routes-using-I.html
https://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/118962-configure-asa-00.html

To use the DMPVN Traffic Segmentation Within DMVPN feature you must configure Multiprotocol Label Switching (MPLS) by using the mpls ip command.

References:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/sec_conn_dmvpn/configuration/xe-16/sec-conn-dmvpn-xe-16-book/sec-conn-dmvpn-dmvpn.html

https://community.cisco.com/t5/network-access-control/bad-invalid-authentication-packet/td-p/824682

When the aggregate-address command is used within BGP routing, the aggregated address is advertised, along with the more specific routes. The exception to this rule is through the use of the summary-only command. The "summary-only" keyword suppresses the more specific routes and announces only the summarized route.

By default, Catalyst switches add a simple uptime timestamp to logging messages. This is a cumulative counter that shows the hours, minutes, and seconds since the switch has been booted up

The correct answer is as follows:

Router(config-router)# passive-interface e0/0

The effect of the passive-interface command is dependent on the routing protocol running on the interface.
For EIGRP, the router will not only stop sending routing updates, but also hellos, which means that it will not form a neighbor relationship with another EIGRP router on that interface. This is also the case with OSPF and IS-IS. With RIP, however, the router will continue to send hellos even as it stops sending routing updates, and it will still receive routing updates.

The passive-interface command issued at the router configuration mode will prevent routing updates from being sent out on a specific interface while still allowing the interface to receive updates. This command can be used in any situation where you want the router to receive routing updates on a particular interface but not send any updates. This is helpful for security purposes, for preventing routing loops, or to control routing update traffic.

The other options either use improper syntax or are executed at an incorrect prompt.

Objective:
Layer 3 Technologies Sub-Objective:
Configure and verify loop prevention mechanisms

References:
Cisco > Home > Support > Technology Support > IP > IP Routing > Design > Design Technotes > How
Does the Passive Interface Feature Work in EIGRP? Cisco > Cisco IOS IP Routing: Protocol-Independent
Command Reference > passive-interface

The following command set will prevent the local router from advertising the 139.10.0.0 network out of the Ethernet 0/0 interface, while allowing all other networks to be advertised:

RouterA(config)# router rip
RouterA(config-router)# network 10.0.0.0
RouterA(config-router)# network 139.10.0.0
RouterA(config-router)# network 199.10.10.0
RouterA(config-router)# distribute-list 10 out e0/0
RouterA(config)# access-list 10 deny 139.10.0.0 0.0.255.255
RouterA(config)# access-list 10 permit any

The distribute-list command allows you to apply a basic access list to a routing process. Just like applying an access list to an interface, when you apply it to a routing process, the permit statements determine what networks may be advertised out the interface. The deny statements determine what networks are not allowed to be advertised out the interface. Instead of applying the access list to an interface, you use the distribute-list command in router configuration mode to apply it to the particular routing process. By specifying an interface and a direction (in or out) in the distribute-list command, you can indicate where the advertisements will be blocked and in what direction.

Keep in mind that when applied this way, the access list does not affect what data traffic passes through the interface. It only affects what networks that the routing protocol will advertise. In the scenario here, RIP will not send advertisements for the 139.10.0.0 network out Ethernet 0/0, but traffic coming from or going to that network is still allowed through the interface in either direction unless there is an access list applied to the interface that will block it.

Conversely, if you applied an access-list to the interface that blocked traffic to or from the 139.10.0.0 network, but permitted all other traffic, it would not stop the routing updates about the 139.10.0.0 from passing through.

Note: The last command in the sequence, RouterA(config)#access-list 10 permit any, is VERY important. If that line is missing, any route not specified with an allow statement will be denied. For example, if you wanted to only allow one network to be advertised, you could configure an allow statement for that network and leave off the permit any parameter. It would block all advertisements with the exception of the one specified by the allow statement.

The following command set is incorrect because the distribute list is applied inbound, which would prevent the reception of updates concerning the 139.10.0.0/16 but would not prevent them from being advertised:

RouterA(config)# router rip
RouterA(config-router)# network 10.0.0.0
RouterA(config-router)# network 139.10.0.0
RouterA(config-router)# network 199.10.10.0
RouterA(config-router)# distribute-list 10 in e0/0
RouterA(config)# access-list 10 deny 139.10.0.0 0.0.255.255
RouterA(config)# access-list 10 permit any

The following command set is incorrect because it applies an access list to the interface instead of a distribute list. The effect would be to block all traffic for that network, but allow routing updates:

RouterA(config)# router rip
RouterA(config-router)# network 10.0.0.0
RouterA(config-router)# network 139.10.0.0
RouterA(config-router)# network 199.10.10.0
RouterA(config-router)# access-group 10 out e0/0
RouterA(config)# access-list 10 deny 139.10.0.0 0.0.255.255
RouterA(config)# access-list 10 permit any

The following command set is incorrect because it also applies an access list instead of a distribute list, this time incoming instead of outgoing:

RouterA(config)# router rip
RouterA(config-router)# network 10.0.0.0

RouterA(config-router)# network 139.10.0.0
RouterA(config-router)# network 199.10.10.0
RouterA(config)# access-list 10 deny 139.10.0.0 0.0.255.255
RouterA(config)# access-list 10 permit any
RouterA(config)# interface e0/0
RouterA(config-if)# access-group 10 out

Objective:
Layer 3 Technologies Sub-Objective:
Configure and verify filtering with any protocol

References:
Cisco > Cisco IOS IP Configuration Guide, Release 12.2 > Configuring IP Routing Protocol-Independent
Features > Filtering Routing Information Cisco > Cisco IOS IP Routing: Protocol-Independent Command
Reference > distribute-list out (IP)

It provides neither authentication nor encryption. In SNMPv3 there are three combinations of security that can be used: noAuthNoPriv-no authentication and no encryption noauth keyword in the configuration AuthNoPriv - messages are authenticated but not encrypted auth keyword in the configuration AuthPriv - messages are authenticated and encrypted priv keyword in the configuration In this case, the keyword noauth in the configuration indicates that no authentication and no encryption are provided. This makes the implementation no more secure than SNMPv1 or SNMPv2.

In SNMPv1 and SNMPv2, authentication is performed using a community string. When you implement SNMP using the noauth keyword, it does not use community strings for authentication. Instead it uses the configured user or group name (in this case NORMAL). Regardless, it does not provide either authentication or encryption.
Objective:
Infrastructure Services Sub-Objective:
Configure and verify SNMP

References:
SNMP Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches) > SNMPv3

The show ip eigrp topology all-links command displays both feasible successors and non-feasible successors to a given destination network. This command displays the contents of the topology table and shows all the routes available for a given destination network.

An example of partial output of the command is below:

The 172.20.2.0/24 network has a feasible successor. This can be determined by looking at the values in the parenthesis next to each route. The second value after the / is the advertised distance from the successor. This value must be less than the value of the feasible distance for a route to be considered a feasible successor. There are two routes for 172.20.2.0/24. The first route listed, via 172.17.3.1, is the successor route. Its cost is 246983122, which matches the feasible distance (FD). The second route, via 172.17.1.1, has an advertised distance of 2443698 (the second value in the parentheses after the /).

Because this value is less than the FD (2413698), it qualifies as a feasible successor.

The 172.25.1.0/24 network does not have a feasible successor. The second route listed via 172.17.1.1 has an advertised distance of 2501649, which is greater than the value of the FD, (2416381). Therefore, it is not a feasible successor.

You should not use the show ip route eigrp command. This command displays only the best metric routes (successors) to a given destination network. A route has the best metric if it has the least feasible distance, which refers to the sum of the metric from a given neighbor to a destination network and the metric to reach that neighbor.

You should not use the show ip eigrp topology command without the all-links parameter. This command displays only the feasible successors to a given destination network.

You should not use the show ip eigrp topology zero-successors command because this command lists those routes that do not have a valid successor.

Objective:
Layer 3 Technologies Sub-Objective:
Configure and verify policy-based routing

References:
Cisco IOS IP Routing: EIGRP Command Reference > show ip eigrp topology

The ip sla reset command is not mandatory for an implementation plan to configure IP SLAs for monitoring IP connections and traffic. This command causes the IP SLA engine to either restart or shutdown. As a result, all IP SLAs operations are stopped, IP SLA configuration information is erased, and IP SLAs are restarted. The IP SLAs configuration information will need to be reloaded to the engine.

The following commands are essential to the implementation plan:

ip sla
ip sla schedule
icmp-echo
The ip sla command allows you to configure IP SLAs operations. When you execute this command in the global configuration mode, it enables the IP SLA configuration mode. In the IP SLA configuration mode, you can configure different IP SLA operations. You can configure up to 2000 operations for a given IP SLA
ID number.

The icmp-echo command allows you to monitor IP connections and traffic on routers by creating an IP SLA ICMP Echo operation. This operation monitors end-to-end response times between routers.

The ip sla schedule command allows you to schedule the IP SLA operation that has been configured. With this command, you can specify when the operation starts, how long the operation runs, and the how long the operation gathers information. For example, if you execute the ip sla schedule 40 start-time now life forever command, the IP SLA operation with the identification number 40 immediately starts running. This is because the now keyword is specified for the start-time parameter. The forever keyword with the life parameter indicates that the operation keeps collecting information indefinitely. Note that you cannot re-configure the IP SLA operation after you have executed the ip sla schedule command.

The information gathered by an IP SLA operation is typically stored in RTTMON-MIB. A Management Information Base (MIB) is a database hosting information required for the management of routers or network devices. The RTTMON-MIB is a Cisco-defined MIB intended for Cisco IOS IP SLAs. RTTMON MIB acts as an interface between the Network Management System (NMS) applications and the Cisco IOS
IP SLAs operations.

Objective:
Infrastructure Services Sub-Objective:
Configure and verify IP SLA

References:
Cisco > Support > Technology Support > IP > IP Application Services > Technology Information >
Technology White Paper > Cisco IOS IP Service Level Agreements User Guide Cisco IOS IP SLAs
Command Reference > icmp-echo through probe-packet priority > ip sla Cisco IOS IP SLAs Command
Reference > icmp-echo through probe-packet priority > ip sla schedule Cisco > Cisco IOS IP SLAs
Command Reference > icmp-echo

In an MPLS network, Service Provider Edge (PE) routers use Multiprotocol Border Gateway Protocol (MP-BGP) to exchange label and route information with each other. MP-BGP is the routing protocol used to create and distribute labels between service provider edge routers on an MPLS network.

The error log is printed prior configuring the virtual link and the stub area. The log actually confirms the fact that r2 tried to establish a virtual link with r3. The 192.168.125.5 is the source IP of the packet that triggered the error and belongs to R2. it is not necessarily the same as the Router ID. Anyway, if the virtual link endpoints are in the stub area, then connectivity between the two routers could be lost. To allow a virtual link to exist through a stub area you should use "virtual-link stub".

This behavior is called starvation and is caused by improper configuration of QoS queues. When TCP and UDP flows are assigned to the same QoS queue, they compete with one another. This is not a fair competition because the TCP packets will react to packet drops by throttling back TCP traffic, while UDP packets are oblivious to drops and will take up the slack created by the diminishing TCP traffic. The results from mixing UDP and TCP traffic in the same queue are: Starvation Latency Lower throughput

While it is true that jitter can be caused by a lack of QoS, jitter is not what is being described in the scenario. Jitter is the variation in latency as measured in the variability over time of the packet latency across a network. This phenomenon seriously impacts time-sensitive traffic, such as VoIP, and can be prevented by placing this traffic in a high-priority QoS queue.

While latency can be caused by the maximum transmission unit (MTU) in the network, this is not a case of latency, although latency may be one of the perceived effects of starvation. Latency is the delay in reception of packets. The MTU is the largest packet size allowed to be transmitted, and an MTU that is set too large can result in latency.

While windowing can be caused by network congestion, this is not a case of windowing. This is a technique used to adjust the number of packets that can acknowledged at once by a receiving computer in a transmission. In times of congestion the window, or number of packets that can be acknowledged at a time, will be small. Later, when congestion goes down, the window size can be increased.

Objective:
Network Principles Sub-Objective:
Describe UDP operations

References:
Design Guide > Service Provider Quality of Service > CE Guidelines for Collapsing Enterprise Classes >
Mixing TCP with UDP

"LA router receives all the NewYork routes but it does not receive any LA routes" because when redistrubuting into EIGRP, we must configure the default metric.

The method used must have been Password Authentication Protocol (PAP). This method transmits the credentials in clear text, which makes it a poor choice.

There are only two methods available to authenticate a PPP connection, PAP and Challenge-Handshake Authentication Protocol (CHAP). CHAP never sends the password across the link. Rather, the authenticating end of the connection sends random text and other information to the requester. The requester encrypts this data with its password and sends it back. The authenticating end of the connection reverses the encryption using the same password and compares the result with what was originally sent. If it matches, the authenticating end of the connection is assured that the requesting end knows the password.

The connection could not have used either 802.1x or IPsec, as neither method would transmit the credentials in clear text.

The connection could not have used CHAP. If it had, the credentials could not have been captured with a sniffer.

Objective:
Layer 2 Technologies Sub-Objective:
Configure and verify PPP

References:
Cisco > Authentication, Authorization, and Accounting Configuration Guide, Cisco IOS Release 15M&T >
Configuring Authentication > Non-AAA Authentication Methods > Enabling CHAP or PAP Authentication
Cisco > Authentication, Authorization, and Accounting Configuration Guide, Cisco IOS Release 15M&T
(PDF)

While the ip helper address command is typically used to forward DHCP broadcasts to a DHCP server located in a remote subnet, it will also forward the following broadcast packets by default as well: TFTP - UDP port 69
Domain Name System (DNS) UDP port 53
Time service - port 37
NetBIOS Name Server - port137
NetBIOS Datagram Server - port 138
Bootstrap Protocol (BOOTP) - port 67
TACACS UDP port 49 Objective:
Infrastructure Services Sub-Objective:
Configure and verify IPv4 and IPv6 DHCP

References:
Cisco IOS IP Application Services Command Reference > ip accounting through ip sctp authenticate > ip
helper-address

debug ip routing This command enables debugging messages related to the routing table.

The correct interface command to set the maximum size of IP packets (maximum transmission unit or MTU size) to 1492 is router(config-if)# ip mtu 1492. This command is required because RFC 2516 states the maximum receive unit (MRU) must not be negotiated larger than 1492 bytes.

All other answers are invalid commands due to incorrect syntax.

Objective:
Network Principles Sub-Objective:
Explain TCP operations

References:
Cisco > Cisco IOS IP Application Services Command Reference > idle (firewall farm datagram protocol)
through ip slb natpool > ip mtu

When you configure an EIGRP summary route, all networks that fall within the range of your summary are suppressed and no longer advertised on the interface. Only the summary route is advertised. But if we want to advertise a network that has been suppressed along with the summary route then we can use leak-map feature. The below commands will fix the configuration in this question:
R1(config)#access-list 1 permit 10.1.1.0 0.0.0.3
R1(config)#route-map Leak-Route permit 10 // this command will also remove the "route_map
Leak-Route deny 10" command.
R1(config-route-map)#match ip address 1

The DHCPv6 Guard feature blocks reply and advertisement messages that come from unauthorized DHCP servers and relay agents. Packets are classified into one of the three DHCP type messages. All client messages are always switched regardless of device role. DHCP server messages are only processed further if the device role is set to server. Further processing of server messages includes DHCP server advertisements (for source validation and server preference) and DHCP server replies (for permitted prefixes). If the device is configured as a DHCP server, all the messages need to be switched, regardless of the device role configuration.

"Although OSPF PE-CE connections assume that the only path between two client sites is across the MPLS VPN backbone, backdoor paths between VPN sites (shown in grey in the figure below) may exist. If these sites belong to the same OSPF area, the path over a backdoor link will always be selected because OSPF prefers intraarea paths to interarea paths. (PE routers advertise OSPF routes learned over the VPN backbone as interarea paths.) For this reason, OSPF backdoor links between VPN sites must be taken into account so that routing is performed based on policy. "

According to this question, uRPF is running in strict mode because packets are dropped even when that route exists in the routing table. Maybe packets are dropped because the receiving interface is different from the interface the local router uses to send packets to that destination.
The ip verify unicast source reachable-via rx command enables Unicast RPF in strict mode.
To enable loose mode, administrators can use the any option (ip verify unicast source reachable-via any).
In loose mode, it doesn't matter if we use this interface to reach the source or not.

The allow-default option allows the use of the default route in the source verification process.

R2 can establish a full adjacency with the neighbor at 192.168.5.107 and the neighbor at 192.168.5.165. In a broadcast, multi-access network OSPF network, full adjacencies can only be established with a designated router (DR) or a backup designated router (BDR).

Objective:
Layer 3 Technologies Sub-Objective:
Configure and verify OSPF neighbor relationship and authentication

References:
Home.Support > Technology Support > IP > IP Routing > Design > Design Technotes > What does the
show ip ospf neighbors command reveal? Cisco > Cisco IOS IP Routing: OSPF Command Reference >
show ip ospf neighbor

The value 30 represents the seed metric for routes that are redistributed from EIGRP into OSPF.

When configuring the OSPF process, the redistribute command is used to identify the source protocol, its AS or process ID, and several other optional parameters, such as metric. The default seed metric for all routing protocols except BGP is 20. When redistributing BGP, the default seed metric is 1.

It does not identify the seed metric associated with OSPF routes that are redistributed into EIGRP. The command is redistributing EIGRP into OSPF, not OSPF into EIGRP.

It does not identify the amount that the existing EIGRP metric will increment as it is redistributed into OSPF. A seed metric value is an absolute value not incremental.

It does not specify that routes that contain metrics of less than 30 will be redistributed from OSPF into EIGRP.
It not used to filter routes.

Objective:
Layer 3 Technologies Sub-Objective:
Configure and verify redistribution between any routing protocols or routing sources
References:
Cisco > Cisco IOS IP Routing: Protocol-Independent Command Reference > redistribute (ip)

References:
https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/7-x/security/configuration/guide/b_Cisco_Nexus_9000_Series_NX-OS_Security_Configuration_Guide_7x/
b_Cisco_Nexus_9000_Series_NX-OS_Security_Configuration_Guide_7x_chapter_011011.pdf

The correct answer is show ip ospf virtual-links. The show ip ospf virtual-links command displays the current state of OSPF virtual links, as shown below.

The following additional commands are available to verify OSPF configurations: show ip ospf border-routers, debug ip ospf adj, and show ip ospf.

The show ip ospf border-routers command displays internal OSPF routing table entries for an ABR, as shown below.

router10#show ip ospf border-routers
Codes: i - Intra-area route, I-Inter-area route

Type Dest Address Cost NextHop Interface ABR ASBR Area SPF
i 2.2.2.2 10 192.1.1.199 Ethernet 2 TRUE FALSE 0 3
i 3.2.2.2 10 192.1.1.200 Ethernet 2 TRUE FALSE 0 3

The show ip ospf command displays information about the router's role and each area to which the router is connected, as shown below.

The debug ip ospf adj command displays information about the state of neighbor adjacencies, as shown below.

R3#debug ip ospf adj OSPF adjacency events debugging is on

00:54:04: OSPF: Rcv pkt from 172.12.23.2, Ethernet0, area 0.0.0.1 : src not on the same network

In the above example, either the IP address or the subnet mask is misconfigured on either this router or the neighbor.

Objective:
Layer 3 Technologies Sub-Objective:
Configure and verify network types, area types, and router types

References:
Cisco > Cisco IOS IP Routing Protocols Command Reference > IP Routing Protocol-Independent
Commands:
S through T > show ip ospf virtual-links

The show ip protocols command gives information about any dynamic routing protocol, including EIGRP.
With respect to EIGRP, it will show the K values as a part of the output. A sample is shown below:

Routing Protocol is "eigrp 77"
Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates EIGRP metric weight K1=1,K2=0,K3=1,K4=0,K5=0 EIGRP maximum, hopcount 100
<output omitted>
The debug ip eigrp command displays real-time information about EIGRP packets that are received and sent. It does not contain K values. A single line of this command output is shown below:

Router# debug ip eigrp
IP-EIGRP: Processing incoming UPDATE packet IP-EIGRP: Ext 192.168.5.0 255.255.255.0 M 386560 - 256000 130560 SM 360960 - 256000 104960
<output omitted>

The debug eigrp packet command displays general debug information, but not K values. A sample of this command output is shown below:

Router# debug eigrp packet
EIGRP: Sending HELLO on Ethernet0/1 AS 109, Flags 0x0, Seq 0, Ack 0 EIGRP: Received UPDATE on Ethernet0/1 from 192.195.78.24, AS 109, Flags 0x1, Seq 1, Ack 0
<output omitted>

The show ip eigrp traffic command displays packets received, as well as statistics on hello packets, updates, queries, and acknowledgments, but not K values. Partial output of this command is shown below:

Router# show ip eigrp traffic IP-EIGRP Traffic Statistics for process 151
Hellos sent/received: 220/205
Updates sent/received: 7/29
Queries sent/received: 2/0
Replies sent/received: 0/2
Acks sent/received: 29/14

Objective:
Layer 3 Technologies Sub-Objective:
Describe and optimize EIGRP metrics

References:
Cisco IOS Master Command List, Release 12.4T > sa ipsec through show ip route dhcp > show ip
protocols

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.

Objective:
Layer 3 Technologies Sub-Objective:
Configure and verify manual and autosummarization with any routing protocol

References:
Cisco > Cisco IOS IP Routing: BGP Command Reference > aggregate-address

The IP Event Dampening feature introduces a configurable exponential decay mechanism to suppress the effects of excessive interface flapping events on routing protocols and routing tables in the network. This feature allows the network operator to configure a router to automatically identify and selectively dampen a local interface that is flapping.

To configure Spoke to Spoke communication we can configure DMVPN Phase II or Phase III. But in Phase II, the first few packets would go through Hub. In order tototally ignore the hub, we have to use DMVPN Phase III: DMVPN Phase III is same as Phase 2 but removes some restrictions and complexities of Phase 2. Also allows greater variety of DMVPN network designs we use: + ip nhrp redirect in hub: tells the initiator spoke to look for a better path to the destination spoke than through the Hub. Upon receiving the NHRP redirect message thespokes communicate with each other over the hub and they have their NHRP replies for the NHRP Resolution Requests that they sent out.
+ ip nhrp shortcut in spokes: overwrite the CEF table on the spoke. It basically overrides the next-hop value for a remote spoke network from the default initial hubtunnel IP address to the NHRP resolved remote spoke tunnel IP address)

NAT64 is a solution when IPv6 hosts need to communicate with IPv4-only servers. When the translation occur on the router the IPv4 address 10.0.0.1 will converted to hex as a00:1 and will be attached to the end of the stateful prefix of 3001::/96 that was configured on the router interface connected to the IPv4
server. The result will be 3001::a00:1.

The address will not be 2001::a001. The prefix that will be attached to the hex version of 10.0.0.1 will not be that of the interface fa0/2/7 but will be the prefix that was configured on that interface for nat64
translation which is 3301::/96. The address will not be 2001::a00:b. That is the IPv6 address on the interface connected to the IPv6 host, but that address is not used for IPv4 to IPv6 communication. A translated address will be generated by converting the IPv4 address of the IPv4 host to hex and attaching it to the IPv6 prefix configured on the interface connected to the IPv4 server.

The address will not be 2001::A00:A. That is the IPv6 address of the IPv6 host. That was statically mapped to 10.0.0.10 in the configuration and as such will be the IPv4 address used by the IPv6 host on the IPv4 side of the router.

Objective:
Infrastructure Services Sub-Objective:
Describe IPv6 NAT

References:
Stateful Network Address Translation 64 (PDF)

The class-map NMS in the exhibit did not classify traffic into specific protocols so many packets were dropped. We should create some class-map to classify the receiving traffic. It is also a recommendation of CoPP/CPP policy: "Developing a CPP policy starts with the classification of the control plane traffic. To that end, the control plane traffic needs to be first identified and separated into different class maps."

References:
https://tools.cisco.com/security/center/resources/copp_best_practices

https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/25160-bgp-maximum-prefix.html#b

https://www.cisco.com/c/en/us/td/docs/routers/7600/ios/15S/configuration/guide/7600_15_0s_book/IPv6_Security.html#62638

https://www.cisco.com/c/en/us/support/docs/wireless/4400-series-wireless-lan-controllers/109597-csr-chained-certificates-wlc-00.html#anc12

The correct command is Router(config-router)# distance 220 0.0.0.0 255.255.255.255 5. This command instructs the router to change the AD for any networks specified in the access list 5 to 220.
The correct syntax for the distance command is shown below:

distance weight [address mask [ access-list-number | name]

The weight parameter is the administrative distance (AD), which is a number from 10 to 255. Note: Distances 0 through 9 are reserved for system use.

To change the administrative distance for an entire routing protocol, use the distance command, as shown below:

Router(config)# router rip

Router(config-router)# distance 125

To change the AD for only selected networks, use an access list with the distance command as shown below:

Router(config)#access-list 5 permit 10.0.0.0 255.0.0.0
Router(config)#access-list 5 permit 11.0.0.0 255.0.0.0
Router(config)#access-list 5 permit 12.0.0.0 255.0.0.0
Router(config)#router rip
Router(config-router)# distance 220 0.0.0.0 255.255.255.255 5

The 0.0.0.0 255.255.255.255 portion included with the distance command could hold an address/mask combination for a single address, but it is more common to use an access list.

Objective:
Layer 3 Technologies Sub-Objective:
Describe administrative distance

References:
Cisco > Cisco IOS IP Routing: Protocol-Independent Command Reference > distance (ip)

Looking at the configuration, it seems that there are two SNMP community strings configured, "public" and "private". However, the configuration does not specify which community string is being used by the host with IP address 10.1.1.1.

The correct action to resolve this issue would be to configure a valid SNMP community string on the device from which the SNMP request is being made, and ensure that it matches the community string configured on the router.

Next Hop Resolution Protocol (NHRP) allows the spoke routers to register their IP addresses with the NHRP server, which is the hub router. It also allows the spoke routers to then learn the physical IP addresses of the other spoke routers from the hub router, allowing for GRE links to be built dynamically as needed between the spokes. This eliminates the need for the traffic to go through the hub router.

Dynamic Multipoint VPN (DMVPN) technology leverages the following associated technologies: IPsec mGRE Dynamic routing protocols NHRP Cisco Express Forwarding

It makes it possible to build the hub router once, and add spokes later, making no additional changes to the hub. The spokes are able to register with the hub and dynamically build their own connections to other spokes using the IP addresses learned from the hub using NHRP. DMVPN also allows IPsec point-to-point GRE tunnels to be built to new spokes with no IPsec peering configuration. The multipoint GRE technology (mGRE) allows a single physical interface on the hub to be used for all spoke connections.

Finally, the routing protocols used by DMVPN allow the routers to share routing information, while Cisco Express Forwarding (CEF) is a switching technology that improves performance while reducing the load on the CPUs of the routers.

Objective:
VPN Technologies Sub-Objective:
Describe DMVPN (single hub)

References:
Cisco > Dynamic Multipoint VPN (DMVPN) Design Guide (Version 1.1) > DMVPN Design Overview

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.

Objective:
Infrastructure Services Sub-Objective:
Configure and verify IP SLA

References:
Home > Support > Technology support > IP > IP application services > Technology information >
Technology white paper > Cisco IOS IP Service Level Agreements User Guide

In this topology, the Hub router will receive advertisements from R2 Spoke router on its tunnel interface.
The problem here is that it also has a connection with R3 Spoke on that same tunnel interface. If we don't disable split-horizon, then the Hub will not relay routes from R2 to R3 and the other way around.That is because it received those routes on the same interface tunnel and therefore it cannot advertise back out that same interface (split-horizon rule). Therefore we must disable splithorizon on the Hub router to make sure the Spokes know about each other.

If the auto-cost reference bandwidth 2000 command is executed in router OSPF mode it will result in a cost to the FastEthernet interfaces of 20. The formula for arriving at the cost is:
reference bandwidth / interface bandwidth = cost
The default reference bandwidth for FastEthernet is 100 Mbps. If the reference bandwidth is set at 2000
Mbps using the auto-cost reference command, and the FastEthernet interface has a bandwidth of 100
Mbps, the resulting cost is 20 (2000 / 100 = 20).

The auto-cost reference bandwidth command is executed in router OSPF mode to affect all interfaces.
Alternatively, the cost of each interface can be set separately with the ip ospf cost command issued in interface configuration mode. The two commands can also be used in combination: you can set all interfaces with the auto-cost reference bandwidth command, and then set a single interface to a different cost with the ip ospf cost command.

The command would not result in the cost of the Serial interface increasing to 20 or to 647. With a reference bandwidth of 2000 Mbps and interface bandwidth of 1544 kbps (the default bandwidth of a serial interface), the resulting cost would be 1294.

Objective:
Layer 3 Technologies Sub-Objective:
Configure and verify OSPF path preference

References:
Cisco > Home > Support > Technology Support > IP > IP Routing > Technology Information > Technology
White Paper > OSPF Design Guide > OSPF Cost Cisco > Cisco IOS IP Routing: OSPF Command
Reference > show ip ospf interface Cisco > Cisco IOS IP Routing: OSPF Command Reference > auto-cost

The command ip nhrp map multicast dynamic should be only used on Hub router, not spoke. If we are running dynamic routing protocols based on multicast (like RIP, OSPF, EIGRP ...) we have to add the command ip nhrp map multicast dynamic in Hub to replicate all multicast traffic to all dynamic entries in the NHRP table (multicast will be proceeded as unicast traffic) - The tunnel source FastEthernet0/0 is equivalent to tunnel source 172.17.0.2, which is the NBMA address of Spoke A.

The correct answer is that IPv4 and IPv6 are running simultaneously on rtrA. The set of commands enables IPv6 on the rtrA router and assigns an IPv4 address and an IPv6 address to the Fa0/0 interface.
This indicates that the router is a dual-stack router on which both IPv4 and IPv6 are running simultaneously.

The IPv4 address is not translated to the IPv6 address by the given set of commands because NAT-PT is not enabled on the router. To enable NAT-PT on a router, you need to use the ipv6 nat command. In addition, the ipv6 nat prefix command should be used to specify an IPv6 prefix.

The IPv6 address is not an IPv4-compatible address. IPv4-compatible IPv6 addresses are used in automatic IPv4-compatible IPv6 tunnels. These addresses refer to those IPv6 unicast addresses that have zeros in the first 96 bits and an IPv4 address in the last 32 bits. For example, 0:0:0:0:0:0:192.156.10.67 is an IPv4- compatible IPv6 address where 192.156.10.67 is an IPv4 address. The IPv6 address (2001:0:1:1:D52::F3C/64), in this case, is not an IPv4-compatible IPv6 address.

A tunnel is not created for the interoperability of the IPv4 and IPv6 addresses because the given set of commands configures the router as a dual-stack router. There are no commands for configuring a tunnel on the router.

Objective:
Network Principles Sub-Objective:
Recognize proposed changes to the network

References:
Cisco IOS IPv6 Configuration Guide, Release 12.4 > Implementing IPv6 Addressing and Basic
Connectivity > Configuration Examples for Implementing IPv6 Addressing and Basic Connectivity >
Example: Dual Protocol Stacks Configuration

R1(config-router)#auto-cost reference-bandwidth ?
<1-4294967> The reference bandwidth in terms of Mbits per second
R1(config-router)#auto-cost reference-bandwidth

https://community.cisco.com/t5/routing/no-exec/td-p/3715737

By tracking the loopback interface and decrementing the priority if it goes down, technicians would have a method of moving the active role to the other router by disabling the loopback interface. This method is less disruptive than disabling any of the physical interfaces. Although no decrement value has been specified, a default decrement of 10 will occur.

This configuration would not be used to prevent this router from ever relinquishing the active role. That would defeat the purpose of Hot Standby Routing Protocol (HSRP), which is to provide failover by relinquishing the active role to the other router.

This configuration would not be used to prevent this router from ever performing the active role. That would defeat the purpose of HSRP which is to provide failover by this router taking the active role when there is an issue with the other router.

This configuration would not be used to allow preemption over multiple peers. When more than two routers are in an HSRP group, the active router is allowed preemption over multiple peers by default.

Objective:
Infrastructure Services Sub-Objective:
Configure and verify tracking objects

References:
Home > Support > Technology support > IP > IP application services > Troubleshoot and alerts >
Troubleshooting Technotes > How to use the standby preempt and standby track commands

The dead interval for OSPF will change to 40 seconds. By default, a Frame Relay connection that uses a physical interface is designated a non-broadcast network for purposes of determining the OSPF hello and dead intervals. There are four possible network types for Frame Relay, and they use different values for the OSPF hello and dead intervals. The values are shown below:

When the ip ospf network point-to-point command is executed, it will change the network type from the default of non-broadcast to point-to-point. This alteration will change the hello and dead intervals to 10 and
40 seconds, respectively.

The hello interval for OSPF will not change to 30 seconds. That is the value for non-broadcast and point-to- multipoint networks.

There will not be a designated router (DR) election. DRs are not elected on a point-to-point network. The hub router does not need to be configured with a router ID. In OSPF for IPv4, the router can create its own by using one of the IP addresses of its interfaces.

Objective:
Layer 2 Technologies Sub-Objective:
Explain Frame Relay

References:
Home > Support > Technology support > Initial Configurations for OSPF over Frame Relay Subinterfaces

One is the number of the HSRP group. Hot Standby Routing Protocol (HSRP) can be used to provide default gateway redundancy for computers sharing the same gateway. At least two routers are gathered into a routing group, which in this case is numbered 1. One of the routers will answer ARP requests for the standby IP address (in this case 171.16.6.100), which is the address the computers will have configured as their default gateway. That router is called the active router.
If that router goes down, then the other router will start answering ARP requests for the standby IP address.

This is not a Gateway Load Balancing Protocol configuration. That is an alternative to HSRP which allows both routers to be used while still providing backup to one another. That configuration would be different in that it uses GLBP groups rather than standby groups, among other differences.

This router will be not prevented from taking back over as active router when it recovers from an outage of its Serial 0 interface. The presence of the command standby 1 preempt indicates that the router can take back over or preempt the other router when it recovers from an outage of its Serial 0 interface. The command standby 1 track Serial0 tells the router to track the up/down state of its Serial 0 interface. If it goes down, it knows to decrement its HSRP priority by 10 (the decrement value). This will drop its HSRP priority to 95. We do not see the priority of the other router in the group, but if for example its priority is 100, this configuration would allow it to take over as active router.

Objective:
Infrastructure Services Sub-Objective:
Configure and verify tracking objects

References:
Home > Support > Technology support > IP > IP application services > Troubleshoot and alerts >
Troubleshooting Technotes > How to Use the standby preempt and standby track Commands

From the output we notice that the destination IP address is not correct. The NMS server IP address should be 10.221.10.11, not 10.221.10.10. Therefore we have to change this information under "flow exporter ..."configuration. NetFlow configuration reference:
https://www.cisco.com/c/en/us/td/docs/iosxml/ios/fnetflow/configuration/15-mt/fnf-15-mt-book/cfg-de-fnflow-exprts.html

DNS64 and NAT64 functions are completely separated when using NAT64. In NAT-PT these two functions are tightly coupled, which reduces flexibility and is why NAT-PT has been deprecated, with the IETF proposing NAT64 as its viable successor.

DNS64 and NAT64 functions are not completely integrated in NAT64, so this is not an advantage of NAT64 over NAT-PT as a translation option.

NAT64 works over non-Ethernet networks. It is NAT-PT that does only works on Ethernet networks.
Therefore, this is not an advantage of NAT 64 over NAT-PT.

NAT64 can reconstruct fragments packets if they are fragmented by an intermediate IPv4 router. It is NAT-PT that will be unable to reconstruct fragments packets if they are fragmented by an intermediate IPv4 router, so this is not an advantage of NAT 64 over NAT-PT.

Objective:
Infrastructure Services Sub-Objective:
Describe IPv6 NAT

References:
Home > Products & services > Cisco IOS and NX-OS software > Cisco IOS technologies > Enterprise IPv6
solution > Data sheets and literature > White papers > NAT64 Technology: Connecting IPv6 and IPv4
Networks > Technologies Facilitating IPv6/IPv4 Translation