300-410 Practice Test 50 — 15 Questions

Question 1

An engineer must ensure that all syslog messages with severity level 4 (warning) and higher are sent to a remote syslog server at 10.1.1.100, while also logging messages of severity 6 (informational) to the console. Which TWO configuration commands are required? (Choose TWO.)

Accepted Answer

logging host 10.1.1.100 trap 4. The 'logging host' command with the 'trap' keyword sets the severity filter for remote logging; default trap level is 6 (informational), so to limit to level 4 and higher, the trap level must be set to 4. The 'logging console' command controls console logging; default is level 7 (debugging), so setting it to 6 allows informational and higher (0-6). The 'logging buffered' command affects buffer logging, not console. The 'logging source-interface' sets the source IP but does not filter severity. The 'logging monitor' affects terminal lines, not console.

Answer

logging buffered 6

Answer

logging source-interface Loopback0

Answer

logging monitor 4

Question 2

An engineer configures OSPF area range on an ABR to summarize routes. After configuration, some routes are still being advertised as individual LSAs into the backbone. Which is the most likely explanation?

Accepted Answer

The area range command does not summarize external routes redistributed into OSPF.. OSPF area range summarization only works for intra-area routes (type 1 and type 2 LSAs). It does not summarize external routes (type 5 LSAs) or routes from other areas (type 3 LSAs) that are being advertised into the area. Additionally, if the range does not exactly match the prefix length, it may not summarize correctly.

Answer

The ABR is not configured with the summary-address command.

Answer

The area range is configured on the wrong ABR.

Answer

The OSPF process needs to be cleared to apply the area range.

Question 3

Which TWO statements about the 'logging rate-limit' command and its effects are correct? (Choose TWO.)

Accepted Answer

The command 'logging rate-limit 200 all' limits all syslog messages to 200 messages per second.. The 'logging rate-limit' command limits the number of syslog messages per second to prevent CPU overload. It can be applied globally or per interface. The 'all' option applies the limit to all messages, while 'except' allows certain severities to bypass the limit. The default rate is not unlimited; it depends on the IOS version but typically no rate limit is applied by default. The command does not affect console logging rate by default; it primarily affects logging to buffer and remote servers. The 'show logging' command displays the current rate-limit configuration.

Answer

By default, Cisco IOS applies a rate limit of 100 messages per second to all logging destinations.

Answer

The 'logging rate-limit' command only affects messages sent to the console port.

Answer

The 'show logging rate-limit' command displays the current rate-limit configuration.

Question 4

An engineer configures OSPF with authentication on a point-to-point link. The adjacency forms, but routes are not being exchanged. Which is the most likely explanation?

Accepted Answer

One router has authentication configured on the interface, and the other has it configured at the area level, causing a mismatch.. OSPF authentication can be configured at the interface level or at the area level. If authentication is configured on one interface but not the other, the adjacency may still form if the authentication type is 'null' (no authentication) on one side. However, if the authentication key is missing or mismatched, the adjacency will not form. In this case, the adjacency forms, but routes are not exchanged because the authentication is not actually enforced on the link; the routers are exchanging hellos but not LSAs due to a mismatch in authentication settings.

Answer

The authentication key is different on both routers.

Answer

The OSPF network type is point-to-multipoint.

Answer

The OSPF process is configured with passive-interface default.

Question 5

Which TWO statements about the 'logging buffered' command and its interaction with other logging commands are correct? (Choose TWO.)

Accepted Answer

The command 'logging buffered 4096' sets the buffer size to 4096 bytes and enables logging to the buffer.. The 'logging buffered' command enables logging to an internal buffer. The size can be specified in bytes. The 'logging console' and 'logging buffered' are independent; disabling one does not affect the other. The 'logging monitor' controls terminal line logging. The 'logging on' command globally enables logging output; without it, no logging occurs. The 'no logging buffered' command disables buffer logging but does not clear the buffer.

Answer

Disabling console logging with 'no logging console' also disables buffered logging.

Answer

The 'logging buffered' command requires 'logging on' to be configured first; otherwise, it has no effect.

Answer

The 'no logging buffered' command clears the buffer and stops all logging to the buffer.

Question 6

An engineer configures OSPFv3 with multiple areas. On the ABR, routes from area 1 are not being advertised into area 0. Which is the most likely explanation?

Accepted Answer

The ABR does not have a direct interface in area 0.. OSPFv3 requires that the ABR have a direct connection to area 0. If the ABR is not directly connected to area 0, it will not advertise inter-area routes. Additionally, OSPFv3 uses the same rule as OSPFv2: an ABR must have at least one interface in area 0 to function as an ABR.

Answer

The ABR has a higher router ID than the other routers.

Answer

The OSPFv3 process is configured with the 'no-redistribution' command.

Answer

The ABR is configured as a stub router.

Question 7

An engineer configures OSPFv2 with a virtual link to connect a non-backbone area to area 0. The virtual link is up, but routes from the non-backbone area are not being advertised into area 0. Which is the most likely explanation?

Accepted Answer

The virtual link is configured only on one router.. A virtual link in OSPF is used to connect a non-backbone area to the backbone. However, the virtual link must be configured on both endpoints, and the transit area must have full connectivity. If the virtual link is up but routes are not being advertised, it could be because the virtual link is not stable or the routers are not acting as ABRs correctly. Additionally, the virtual link does not automatically make the router an ABR; the router must have a direct connection to area 0 via the virtual link.

Answer

The transit area is a stub area.

Answer

The OSPF process is configured with 'no-virtual-link' command.

Answer

The router IDs are not reachable via the transit area.

Question 8

An engineer configures OSPF on two routers connected via a serial link. Both routers show the neighbor state as EXSTART/EXSTART, and no LSAs are exchanged. The engineer verifies that the OSPF process IDs are the same, areas match, and authentication is correct. Which is the most likely explanation?

Accepted Answer

MTU mismatch between the two routers. In OSPF, when neighbors are stuck in EXSTART, it often indicates an MTU mismatch. OSPF uses the interface MTU to determine the size of Database Description (DBD) packets. If the MTU differs, the receiving router will reject DBD packets larger than its own MTU, causing the neighbor to remain in EXSTART. This is a common edge case because MTU is not always checked during initial troubleshooting.

Answer

OSPF network type mismatch (e.g., point-to-point vs broadcast)

Answer

OSPF hello interval mismatch

Answer

OSPF dead interval mismatch

Question 9

An engineer configures OSPFv3 with a filter-list on an ABR to filter prefixes. After configuration, the routes are still being advertised. Which is the most likely explanation?

Accepted Answer

The filter-list only filters inter-area prefixes, not external routes.. In OSPFv3, prefix filtering is done using the 'prefix-list' or 'filter-list' command under the area. However, the filter-list in OSPFv3 filters type 3 LSAs (inter-area prefixes) but not type 5 LSAs (external routes). If the routes being advertised are external, the filter-list will not affect them.

Answer

The filter-list is applied to the wrong area.

Answer

The filter-list uses an incorrect prefix-list.

Answer

The OSPFv3 process needs to be restarted.

Question 10

An engineer configures EIGRP named mode on two routers. The engineer notices that route summarization configured under the interface does not generate a summary route in the routing table, even though the component routes are present. The engineer confirms that the summary address is correct and the interface is up. Which is the most likely explanation?

Accepted Answer

The interface is not configured under the EIGRP address-family in named mode. In EIGRP named mode, route summarization is configured under the interface configuration mode using the 'summary-address' command, but it requires that the interface is part of the EIGRP address-family under that named mode. If the interface is not explicitly configured under the address-family, the summary-address command is accepted but does not take effect. This is a common edge case because the CLI accepts the command without error, but the summary is not generated.

Answer

The summary-address command must be configured under the EIGRP process, not the interface

Answer

The component routes have a higher administrative distance than the summary

Answer

The summary-address command requires the 'leak-map' option to be specified

Question 11

A network engineer is troubleshooting a BGP peering issue between two directly connected routers, R1 and R2. R1 is configured with 'neighbor 10.1.1.2 remote-as 65002' and 'neighbor 10.1.1.2 update-source Loopback0', while R2 uses 'neighbor 10.1.1.1 remote-as 65001' and 'neighbor 10.1.1.1 update-source Loopback0'. The loopback interfaces are not advertised into any IGP, and there is no static route for the loopback addresses. The BGP session remains in Idle state. What is the most likely cause?

Accepted Answer

The BGP session is stuck in Idle because the neighbor statements reference loopback interfaces that are not reachable.. BGP requires reachability to the neighbor's update-source address. Since the loopback addresses are not reachable via any routing protocol or static route, the TCP connection fails, keeping the session in Idle state.

Answer

The BGP session is stuck in Idle because the remote-as values are mismatched.

Answer

The BGP session is stuck in Idle because the update-source command is not allowed on directly connected interfaces.

Answer

The BGP session is stuck in Idle because the neighbor statements must use the directly connected interface IP addresses.

Question 12

An engineer configures iBGP between two routers in the same AS. The engineer notices that routes learned from one iBGP neighbor are not being advertised to another iBGP neighbor, even though the next-hop is reachable. The engineer verifies that the BGP session is established and that the routes are present in the BGP table. Which is the most likely explanation?

Accepted Answer

iBGP split-horizon rule prevents advertising iBGP-learned routes to other iBGP neighbors. By default, iBGP routers do not advertise routes learned from one iBGP neighbor to another iBGP neighbor because of the split-horizon rule. This is a fundamental behavior to prevent routing loops, but it often catches engineers who expect iBGP to behave like eBGP. To overcome this, a route reflector or confederation must be used.

Answer

The next-hop-self command is required for iBGP

Answer

The BGP synchronization rule is enabled

Answer

The routes are not valid because the next-hop is not reachable

Question 13

An engineer is troubleshooting a missing BGP route on R3. R3 has an eBGP session with R4 (AS 65004) and an iBGP session with R1 (AS 65003). R4 advertises a prefix 192.168.1.0/24 to R3, and R3's BGP table shows the route with next-hop 10.1.4.4. However, R3 does not install this route in its routing table. The output of 'show ip bgp 192.168.1.0/24' on R3 shows the route as valid but not best. What is the most likely cause?

Accepted Answer

The route is not installed because the next-hop 10.1.4.4 is not reachable via any routing table entry.. For an eBGP route to be installed, the next-hop must be reachable via an IGP or static route. If the next-hop is not reachable, BGP marks the route as valid but not best.

Answer

The route is not installed because BGP synchronization is enabled and the IGP does not have the route.

Answer

The route is not installed because the prefix length is too long for the routing table.

Answer

The route is not installed because R3 has a higher administrative distance for eBGP routes.

Question 14

An engineer configures mutual redistribution between OSPF and EIGRP. After a few minutes, the network becomes unstable with routing loops. The engineer checks the routing tables and notices that the same prefix is being learned from both protocols with different administrative distances. Which is the most likely explanation?

Accepted Answer

Routes are redistributed back and forth between OSPF and EIGRP without any filtering or tagging. Mutual redistribution without proper route tagging can cause routing loops because each protocol redistributes routes back into the other, creating a feedback loop. The administrative distance of the redistributed routes may cause one protocol to prefer the redistributed route over the original, leading to instability. Using route tags and filtering can prevent this, but without them, loops are common.

Answer

The seed metric for OSPF redistribution into EIGRP is not configured

Answer

The administrative distance of OSPF is lower than EIGRP, causing OSPF routes to be preferred

Answer

The redistribute command is missing the subnets keyword under OSPF

Question 15

A network engineer is troubleshooting a BGP route advertisement issue. Router R1 in AS 65001 is configured to redistribute connected routes into BGP. The route 10.10.10.0/24 is learned via BGP on R2 (AS 65002), but R2's iBGP neighbor R3 (AS 65002) does not receive this route. R2 and R3 have a full iBGP mesh, and the BGP session is established. The output of 'show ip bgp' on R2 shows the route with the 'r' flag (RIB-failure). What is the most likely cause?

Accepted Answer

The route is marked as RIB-failure because a route with a lower administrative distance already exists in the routing table for the same prefix.. RIB-failure indicates that BGP learned a route but it was not installed in the routing table because a better route (e.g., from an IGP or static) already exists. This prevents the route from being advertised to iBGP peers.

Answer

The route is marked as RIB-failure because the next-hop is unreachable.

Answer

The route is marked as RIB-failure because BGP synchronization is enabled and the IGP does not have the route.

Answer

The route is marked as RIB-failure because the prefix is being filtered by an outbound route map.