OSPF type 1 route is always preferred over a type 2 route for the same destination so we can set

metric-type 1 at Site-A RTR1 so that it is preferred over Site-B RTR2.

Note:

Routes are redistributed in OSPF as either type 1 (E1) routes or type 2 (E2) routes, with type 2 being

the default.

– A type 1 route has a metric that is the sum of the internal OSPF cost and the external redistributed

cost.

– A type 2 route has a metric equal only to the redistributed cost.

– If routes are redistributed into OSPF as type 2 then every router in the OSPF domain will see the

same cost to reach the external networks.

– If routes are redistributed into OSPF as type 1, then the cost to reach the external networks could

vary from router to router.

The Time Domain Reflectometer (TDR) feature allows you to determine if a cable is OPEN or SHORT

when it is at fault.

To start the TDR test, perform this task:

Step 1 (Starts the TDR test): test cable-diagnostics tdr {interface {interface-number}}

Step 2 (Displays the TDR test counter information): show cable-diagnostics

tdr {interface interface-number}

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9600/software/release/16-

11/configuration_guide/int_hw/b_1611_int_and_hw_9600_cg/checking_port_status_and_connectivity

pdf

Text, table Description automatically generated

IPv6 ND inspection learns and secures bindings for stateless autoconfiguration addresses in Layer 2 neighbor tables. IPv6 ND inspection analyzes neighbor discovery messages in order to build a trusted binding table database, and IPv6 neighbor discovery messages that do not have valid bindings are dropped. A neighbor discovery message is considered trustworthy if its IPv6-to-MAC mapping is verifiable.

This feature mitigates some of the inherent vulnerabilities for the neighbor discovery mechanism, such as attacks on duplicate address detection (DAD), address resolution, device discovery, and the neighbor cache.

Option B configures area 7 as a not-so-stubby area (NSSA) with the no-summary option on the area border router (ABR) R4. This allows the injection of external routes from EIGRP into the OSPF domain as type 7 LSAs, while preventing the propagation of inter-area summary LSAs into area 7. The no-summary option also generates a default summary route for area 7, which can be used by R9 to reach the internet2.

Option A configures area 7 as a stub area, which does not allow any external routes or type 7 LSAs in the area. This prevents R9 from learning the EIGRP routes and accessing the internet3.

Option C configures area 7 as a NSSA without the no-summary option on R4. This allows the injection of type 7 LSAs into the area, but also allows the propagation of inter-area summary LSAs into the area. However, this option does not generate a default summary route for area 7, which means R9 has no route to reach the internet4.

Option D configures area 7 as a NSSA with the default-information originate option on R4. This allows the injection of type 7 LSAs into the area, but also allows the propagation of inter-area summary LSAs into the area. The default-information originate option generates a type 7 default route for area 7, which can be used by R9 to reach the internet. However, this option is redundant and less efficient than Option B, because it injects both a type 3 and a type 7 LSA for the default route into the area5.

The last command “aaa authentication login telnet group TAC-SERV” created the method list name

telnet so we need to assign it to line vty.