Question 200
A network team addresses this situation: An upstream BGP peer suddenly advertises a default route and private prefixes not authorized by policy. After the corrective action, which test or result BEST verifies that the problem is resolved?
- Trace traffic to an unlisted external address via the border.
- Look up addresses inside and outside the /24 to compare selected paths.
- Power off the active gateway and time reachability through the standby.
- Inspect accepted route entries after injecting a prohibited test prefix.
Explanation
Correct Answer
D:Inspect accepted route entries after injecting a prohibited test prefix.
Incorrect Answers
A:The first routed hop confirms default forwarding. It does not inspect accepted route entries after injecting a prohibited test prefix.
B:Look up addresses inside and outside the /24 to compare selected paths. It does not inspect accepted route entries after injecting a prohibited test prefix.
C:Communication between different IP subnets requires a routed interface or gateway rather than Layer 2 bridging alone.
Question 201
A network specialist investigates this evidence: An upstream BGP peer suddenly advertises a default route and private prefixes not authorized by policy. Which underlying condition BEST explains the observed failure or requirement?
- The neighbor import policy accepts unwanted networks.
- No gateway of last resort is installed.
- Address-only one-to-one NAT cannot distinguish all concurrent shared flows.
- Longest-prefix selection has priority over a broader route's metric.
Explanation
Correct Answer
A:The neighbor import policy accepts unwanted networks. BGP policy controls which externally learned routes enter selection.
Incorrect Answers
B:Communication between different IP subnets requires a routed interface or gateway rather than Layer 2 bridging alone. The missing change involves the neighbor import policy accepts unwanted networks.
C:NAT rewrites connection addresses or ports according to an explicit translation rule. That does not establish the neighbor import policy accepts unwanted networks.
D:Longest-prefix selection has priority over a broader route's metric. That does not establish the neighbor import policy accepts unwanted networks.
Question 202
A network team observes: A router learns the same 172.20.0.0/16 via static and OSPF routes, but uses the static route even with a higher OSPF bandwidth. What is the MOST appropriate corrective action or technical decision?
- Add an approved 0.0.0.0/0 default route to the border gateway.
- Adjust intended administrative preferences or remove the unwanted static route.
- Correct the OSPF area on the affected interface to match its intended neighbor.
- Correct the /24 next hop or prefix if its route is undesirable.
Explanation
Correct Answer
B:Administrative distance chooses among route sources before metrics of each protocol. Route source preference precedes path metric when prefixes match.
Incorrect Answers
A:Adding an approved 0.0.0.0/0 default route to the border gateway would not adjust intended administrative preferences or remove the unwanted static route.
C:Correcting the OSPF area on the affected interface to match its intended neighbor would not adjust intended administrative preferences or remove the unwanted static route.
D:Correcting the /24 next hop or prefix if its route is undesirable would not adjust intended administrative preferences or remove the unwanted static route.
Question 203
A network team addresses this situation: A router learns the same 172.20.0.0/16 via static and OSPF routes, but uses the static route even with a higher OSPF bandwidth. After the corrective action, which test or result BEST verifies that the problem is resolved?
- Trace traffic to an unlisted external address via the border.
- Ping both gateway subinterfaces and capture their VLAN tags.
- Verify the selected route source and next hop after controlled policy change.
- Look up addresses inside and outside the /24 to compare selected paths.
Explanation
Correct Answer
C:IP routing depends on a route to the destination prefix and a reachable next hop. Verification of this result involves verifying the selected route source and next hop after controlled policy change.
Incorrect Answers
A:The first routed hop confirms default forwarding. That check cannot demonstrate a valid Layer 3 route toward the remote subnet.
B:Per-VLAN tags and gateway success demonstrate inter-VLAN routing. Verification of this result involves verifying the selected route source and next hop after controlled policy change.
D:Look up addresses inside and outside the /24 to compare selected paths. That check cannot demonstrate a valid Layer 3 route toward the remote subnet.
Question 204
A network specialist investigates this evidence: A router learns the same 172.20.0.0/16 via static and OSPF routes, but uses the static route even with a higher OSPF bandwidth. Which underlying condition BEST explains the observed failure or requirement?
- No gateway of last resort is installed.
- The route table lacks a valid destination prefix entry.
- The trunk lacks matching 802.1Q routed subinterfaces.
- Route source preference precedes path metric when prefixes match.
Explanation
Correct Answer
D:Route source preference precedes path metric when prefixes match. Administrative distance chooses among route sources before metrics of each protocol.
Incorrect Answers
A:Communication between different IP subnets requires a routed interface or gateway rather than Layer 2 bridging alone. The missing change involves routing source preference precedes path metric when prefixes match.
B:IP routing depends on a route to the destination prefix and a reachable next hop. That does not route source preference precedes path metric when prefixes match.
C:VLAN membership and 802.1Q tagging determine which Layer 2 broadcast domain carries each frame. That does not route source preference precedes path metric when prefixes match.
Question 205
A network team observes: A /24 route has a higher metric than a /16 route, yet packets inside the /24 follow the specific entry. What is the MOST appropriate corrective action or technical decision?
- Correct the /24 next hop or prefix if its route is undesirable.
- Adjust intended administrative preferences or remove the unwanted static route.
- Enforce symmetric translated session routing or supported state synchronization.
- Apply explicit inbound prefix and route-policy filtering on the BGP session.
Explanation
Correct Answer
A:Longer matching network masks are evaluated before metric comparison. Longest-prefix selection has priority over a broader route's metric.
Incorrect Answers
B:Adjusting intended administrative preferences or remove the unwanted static route would not correct the /24 next hop or prefix if its route is undesirable.
C:Enforcing symmetric translated session routing or supported state synchronization would not correct the /24 next hop or prefix if its route is undesirable.
D:Applying explicit inbound prefix and routing-policy filtering on the BGP session would not correct the /24 next hop or prefix if its route is undesirable.
Question 206
A network team addresses this situation: A /24 route has a higher metric than a /16 route, yet packets inside the /24 follow the specific entry. After the corrective action, which test or result BEST verifies that the problem is resolved?
- Verify the selected route source and next hop after controlled policy change.
- Look up addresses inside and outside the /24 to compare selected paths.
- Inspect accepted route entries after injecting a prohibited test prefix.
- Trace traffic to an unlisted external address via the border.
Explanation
Correct Answer
B:Look up addresses inside and outside the /24 to compare selected paths.
Incorrect Answers
A:IP routing depends on a route to the destination prefix and a reachable next hop. That check cannot demonstrate look up addresses inside and outside the /24 to compare selected paths.
C:Inspect accepted route entries after injecting a prohibited test prefix. That check cannot demonstrate look up addresses inside and outside the /24 to compare selected paths.
D:The first routed hop confirms default forwarding. That check cannot demonstrate look up addresses inside and outside the /24 to compare selected paths.
Question 207
A network specialist investigates this evidence: A /24 route has a higher metric than a /16 route, yet packets inside the /24 follow the specific entry. Which underlying condition BEST explains the observed failure or requirement?
- Route source preference precedes path metric when prefixes match.
- The neighbor import policy accepts unwanted networks.
- Longest-prefix selection has priority over a broader route's metric.
- The return path lacks the original translation state.
Explanation
Correct Answer
C:Longest-prefix selection has priority over a broader route's metric. Longer matching network masks are evaluated before metric comparison.
Incorrect Answers
A:Route source preference precedes path metric when prefixes match. That does not establish longest-prefix selection has priority over a broader route's metric.
B:The neighbor import policy accepts unwanted networks. That does not establish longest-prefix selection has priority over a broader route's metric.
D:Stateful NAT requires return traffic to match its stored flow mapping. That does not establish longest-prefix selection has priority over a broader route's metric.
Question 208
A network team observes: Hundreds of private office clients need outbound access through one public IPv4 address. What is the MOST appropriate corrective action or technical decision?
- Configure a carefully restricted static NAT mapping with firewall policy.
- Enforce symmetric translated session routing or supported state synchronization.
- Establish appropriately filtered eBGP neighbor sessions with approved prefix advertisements.
- Use source port address translation with unique session port mappings.
Explanation
Correct Answer
D:PAT shares one public IP by translating source ports and recording flows. Address-only one-to-one nat cannot distinguish all concurrent shared flows.
Incorrect Answers
A:Configuring a carefully restricted static NAT mapping with firewall policy would not meet the need for source port address translation with unique session port mappings.
B:Enforcing symmetric translated session routing or supported state synchronization would not meet the need for source port address translation with unique session port mappings.
C:Establishing appropriately filtered eBGP neighbor sessions with approved prefix advertisements would not meet the need for source port address translation with unique session port mappings.
Question 209
A network team addresses this situation: Hundreds of private office clients need outbound access through one public IPv4 address. After the corrective action, which test or result BEST verifies that the problem is resolved?
- Open simultaneous outbound sessions from two internal hosts and inspect translations.
- Connect from an approved external host and inspect the NAT entry.
- Trace both directions and confirm state lookup on the reply firewall.
- Inspect accepted route entries after injecting a prohibited test prefix.
Explanation
Correct Answer
A:Open simultaneous outbound sessions from two internal hosts and inspect translations.
Incorrect Answers
B:Inbound mapped traffic validates the fixed mapping. That check cannot demonstrate open simultaneous outbound sessions from two internal hosts and inspect translations.
C:Stateful firewalls can distinguish permitted connection initiation from return traffic. That check cannot demonstrate open simultaneous outbound sessions from two internal hosts and inspect translations.
D:Inspect accepted route entries after injecting a prohibited test prefix. That check cannot demonstrate open simultaneous outbound sessions from two internal hosts and inspect translations.
Question 210
A network specialist investigates this evidence: Hundreds of private office clients need outbound access through one public IPv4 address. Which underlying condition BEST explains the observed failure or requirement?
- The internet-facing service lacks a deterministic inbound translation.
- Address-only one-to-one NAT cannot distinguish all concurrent shared flows.
- The return path lacks the original translation state.
- Internet external routing requires interdomain policy exchange.
Explanation
Correct Answer
B:Address-only one-to-one NAT cannot distinguish all concurrent shared flows. PAT shares one public IP by translating source ports and recording flows.
Incorrect Answers
A:The internet-facing service lacks a deterministic inbound translation. That does not establish the intended translated source or destination path.
C:Stateful NAT requires return traffic to match its stored flow mapping. That does not establish the intended translated source or destination path.
D:Internet external routing requires interdomain policy exchange. That does not establish the intended translated source or destination path.
CompTIA Network+ (N10-009) Practice Tests