Administrative Distance

A network engineer is troubleshooting a BGP route reachability issue. R1 learns the prefix 10.1.1.0/24 via eBGP from R2 with an AD of 20, and via OSPF from R3 with an AD of 110. The engineer notices that R1 installs the OSPF route in the routing table instead of the eBGP route, even though the eBGP route is preferred by default. What is the most likely cause of this behavior?

An engineer is troubleshooting a network where R1 and R2 are running EIGRP, and R2 redistributes a static route for 192.168.1.0/24 into EIGRP. R1 also learns the same prefix via OSPF from R3 with an AD of 110. The engineer observes that R1 prefers the EIGRP external route (AD 170) over the OSPF route. What configuration change would cause this behavior?

A network engineer is troubleshooting a connectivity issue between two sites. R1 learns the prefix 10.0.0.0/8 via RIP (AD 120) from R2, and also via a directly connected interface on R3. The engineer notices that R1 uses the RIP route instead of the connected route. What is the most likely cause?

An engineer is troubleshooting a routing loop between two routers. R1 and R2 are running both OSPF and EIGRP. R1 learns the prefix 172.16.1.0/24 via OSPF with AD 110 and via EIGRP internal with AD 90. The engineer notices that R1 installs the EIGRP route, but traffic to 172.16.1.0/24 is being dropped. What is the most likely issue?

A network engineer is troubleshooting a multi-homed BGP setup. R1 receives the prefix 10.1.1.0/24 from two eBGP peers: R2 (AS 100) and R3 (AS 200). The engineer configures the distance bgp 20 20 20 command on R1 to make all BGP routes have the same AD. However, R1 still prefers the route from R2 over R3. What is the most likely reason?

An engineer is troubleshooting a route redistribution issue between OSPF and EIGRP. R1 runs both protocols and redistributes OSPF into EIGRP. The engineer notices that OSPF routes redistributed into EIGRP have an AD of 170, but some routes from OSPF are not being redistributed. What is the most likely cause?

A network engineer is troubleshooting a situation where R1 has two routes to 10.0.0.0/8: one via OSPF (AD 110) and one via RIP (AD 120). The engineer wants R1 to prefer the RIP route. After configuring the distance 80 0.0.0.0 255.255.255.255 under the RIP process, the RIP route is still not preferred. What is the most likely reason?

An engineer is troubleshooting a network where R1 and R2 are running iBGP, and R1 learns the prefix 192.168.1.0/24 from R2 with an AD of 200. R1 also learns the same prefix via OSPF from R3 with AD 110. The engineer notices that R1 uses the iBGP route. What configuration change would cause this?

A network engineer is troubleshooting a route selection issue between two routing protocols. R1 learns the prefix 10.0.0.0/8 via both IS-IS (AD 115) and OSPF (AD 110). The engineer wants R1 to prefer the IS-IS route. After configuring the distance 105 ip 10.0.0.0 0.255.255.255 under the IS-IS process, the IS-IS route is still not preferred. What is the most likely cause?

A network engineer runs the following command on Router R1: R1# show ip route 10.1.1.0 Routing entry for 10.1.1.0/24 Known via "eigrp 100", distance 170, metric 30720 Redistributing via eigrp 100 Last update from 192.168.1.2 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 192.168.1.2, from 192.168.1.2, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 30720, traffic share count is 1 Based on this output, which statement is correct?

A network engineer runs the following command on Router R2: R2# show ip route 192.168.10.0 Routing entry for 192.168.10.0/24 Known via "ospf 1", distance 110, metric 20 Redistributing via ospf 1 Last update from 10.0.0.1 on GigabitEthernet0/1, 00:00:10 ago Routing Descriptor Blocks: * 10.0.0.1, from 10.0.0.1, 00:00:10 ago, via GigabitEthernet0/1 Route metric is 20, traffic share count is 1 Based on this output, what is the most likely origin of this route?

A network engineer runs the following command on Router R3: R3# show ip route 172.16.1.0 Routing entry for 172.16.1.0/24 Known via "bgp 65000", distance 20, metric 0 Redistributing via bgp 65000 Last update from 192.168.1.1 00:00:15 ago Routing Descriptor Blocks: * 192.168.1.1, from 192.168.1.1, 00:00:15 ago Route metric is 0, traffic share count is 1 Based on this output, what can be concluded about the administrative distance?

A network engineer runs the following command on Router R4: R4# show ip route 10.10.10.0 Routing entry for 10.10.10.0/24 Known via "connected", distance 0, metric 0 (connected) Redistributing via eigrp 100 Last update from 10.10.10.1 on GigabitEthernet0/0, 00:00:00 ago Routing Descriptor Blocks: * 10.10.10.1, via GigabitEthernet0/0 Route metric is 0, traffic share count is 1 Based on this output, which statement is true?

A network engineer runs the following command on Router R5: R5# show ip route 192.168.100.0 Routing entry for 192.168.100.0/24 Known via "static", distance 1, metric 0 Redistributing via ospf 1 Last update from 10.0.0.2 on GigabitEthernet0/1, 00:00:05 ago Routing Descriptor Blocks: * 10.0.0.2, via GigabitEthernet0/1 Route metric is 0, traffic share count is 1 Based on this output, what is the likely issue if this route is not being preferred over an EIGRP route with distance 90?

A network engineer runs the following command on Router R6: R6# show ip route 10.0.0.0 Routing entry for 10.0.0.0/8 Known via "eigrp 100", distance 90, metric 28160 Redistributing via eigrp 100 Last update from 192.168.1.1 on GigabitEthernet0/0, 00:00:10 ago Routing Descriptor Blocks: * 192.168.1.1, from 192.168.1.1, 00:00:10 ago, via GigabitEthernet0/0 Route metric is 28160, traffic share count is 1 Additionally, an OSPF route for the same prefix is learned with distance 110. Which route will be installed in the routing table?

A network engineer runs the following command on Router R7: R7# show ip route 172.16.0.0 Routing entry for 172.16.0.0/16 Known via "bgp 65000", distance 200, metric 0 Redistributing via bgp 65000 Last update from 10.0.0.1 00:00:20 ago Routing Descriptor Blocks: * 10.0.0.1, from 10.0.0.1, 00:00:20 ago Route metric is 0, traffic share count is 1 Based on this output, what type of BGP route is this?

A network engineer runs the following command on Router R8: R8# show ip route 10.2.2.0 Routing entry for 10.2.2.0/24 Known via "eigrp 100", distance 90, metric 28160 Redistributing via eigrp 100 Last update from 192.168.2.1 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 192.168.2.1, from 192.168.2.1, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 28160, traffic share count is 1 R8 also has a static route to 10.2.2.0/24 with next-hop 192.168.3.1 configured with distance 95. Which route will be used?

A network engineer runs the following command on Router R9: R9# show ip route 192.168.50.0 Routing entry for 192.168.50.0/24 Known via "ospf 1", distance 110, metric 20 Redistributing via ospf 1 Last update from 10.0.0.1 on GigabitEthernet0/0, 00:00:10 ago Routing Descriptor Blocks: * 10.0.0.1, from 10.0.0.1, 00:00:10 ago, via GigabitEthernet0/0 Route metric is 20, traffic share count is 1 R9 also has an EIGRP route for the same prefix with distance 90 and metric 28160. Which route will be installed?

Consider the following partial configuration on a Cisco IOS-XE router: ``` router eigrp 100 network 10.0.0.0 distance eigrp 90 170 ``` What is the effect of the `distance eigrp 90 170` command?

Given the following configuration on a router: ``` router ospf 1 distance 150 ``` What is the effect of this configuration?

Examine this configuration snippet: ``` router rip distance 120 ``` Which statement is true about the effect of this command?

Consider the following configuration on a router running BGP and OSPF: ``` router bgp 65000 distance bgp 20 200 200 ``` What is the effect of this command?

A network engineer configures the following on a router: ``` router eigrp 100 distance 150 10.0.0.0 0.255.255.255 ``` What is the intended effect?

Examine this configuration: ``` router ospf 1 distance ospf intra-area 150 inter-area 160 external 170 ``` What is the effect of this command?

What is the default administrative distance for OSPF routes on a Cisco IOS-XE router?

Which of the following protocols has the lowest default administrative distance on a Cisco router?

According to Cisco IOS default behavior, if a router learns the same route via both RIP and OSPF, which route will be installed in the routing table?

Which TWO commands can be used to verify the administrative distance of a route in a Cisco IOS router? (Choose TWO.)

Which TWO statements about administrative distance are true? (Choose TWO.)

Which TWO configuration steps are required to change the administrative distance for routes learned from a specific neighbor in EIGRP? (Choose TWO.)

Which THREE symptoms indicate that an administrative distance misconfiguration might be causing routing issues? (Choose THREE.)

Which THREE statements about administrative distance are true when comparing OSPF and EIGRP? (Choose THREE.)

In a multi-area OSPF network, Router R1 (ABR) is redistributing a static default route into OSPF with 'default-information originate always metric 10'. Router R2, an internal router in Area 1, receives the default route but also learns a more specific route to 0.0.0.0/0 via EIGRP from Router R3 with administrative distance 170. The 'show ip route 0.0.0.0' on R2 shows the EIGRP route as the best path. However, R2's 'show ip ospf database external' shows the OSPF external default route. What is the root cause of R2 preferring the EIGRP route?

Router R1 and R2 are running EIGRP as the IGP, and R1 is redistributing a connected subnet 10.1.1.0/24 into EIGRP. R2 also runs BGP with an external peer, and BGP is redistributing the same prefix 10.1.1.0/24 into EIGRP with a route-map that sets the administrative distance to 100. On R3, a downstream EIGRP router, 'show ip route 10.1.1.0' shows the route via R2. What is the most likely cause of suboptimal routing?

Router R1 and R2 are iBGP peers in the same AS. R1 learns a route 172.16.1.0/24 from an eBGP peer with AS_PATH 100 200. R2 learns the same prefix from another eBGP peer with AS_PATH 100. Both routers redistribute the route into OSPF with default administrative distance. R3, an OSPF internal router, sees two OSPF external routes for 172.16.1.0/24: one from R1 (type-5, metric 20) and one from R2 (type-5, metric 30). R3's 'show ip route 172.16.1.0' shows the route via R1. What is the root cause of R3 preferring the route via R1?

Router R1 and R2 are connected via a serial link running OSPF. R1 has 'ip ospf network point-to-point' configured on the interface, while R2 has default broadcast network type. R1's 'show ip ospf neighbor' shows R2 in FULL state, but R2's 'show ip ospf neighbor' shows R1 in FULL state. However, R1's routing table does not contain a route to a subnet 10.10.10.0/24 that is advertised by R2 via a type-3 LSA. R2's 'show ip route 10.10.10.0' shows it as connected. What is the root cause?

In a DMVPN phase 3 network, Router R1 (hub) and R2 (spoke) have an mGRE tunnel. R1 has EIGRP configured over the tunnel with 'no ip split-horizon' and 'distance eigrp 90 100'. R2 has default EIGRP configuration. R2 learns a route to 192.168.1.0/24 via the tunnel with AD 90. Later, R2 also learns the same route via a physical interface from another spoke R3 using EIGRP with AD 90. R2's 'show ip route 192.168.1.0' shows the route via R3. What is the root cause?

Router R1 and R2 are running OSPF and BGP. R1 is an ASBR redistributing BGP routes into OSPF. R2 is an ABR between area 0 and area 1. R2 has 'distance ospf external 150' configured. R3 in area 1 learns a BGP-redistributed route 10.0.0.0/8 via R2 with AD 150. R3 also learns the same prefix via a different path from R4 (another ABR) with AD 110 (default OSPF external). R3's 'show ip route 10.0.0.0' shows the route via R4. What is the root cause?

Router R1 and R2 are running EIGRP. R1 has a route to 172.16.0.0/16 with AD 90. R2 redistributes a static route for 172.16.0.0/16 into EIGRP with a route-map that sets the administrative distance to 85. R1 learns the redistributed route with AD 85 and installs it, overriding the original internal route. However, R1's 'show ip route 172.16.0.0' shows the route via R2 with AD 85, but pings to 172.16.1.1 fail. What is the most likely cause?

Router R1 and R2 are iBGP peers. R1 learns a route 10.10.10.0/24 from an eBGP peer with local preference 200. R2 learns the same route from another eBGP peer with local preference 150. Both routers redistribute the route into OSPF with default settings. R3, an OSPF router, receives two type-5 LSAs for 10.10.10.0/24: one from R1 with metric 20, one from R2 with metric 10. R3's 'show ip route 10.10.10.0' shows the route via R1. What is the root cause?

Router R1 and R2 are running OSPF in area 0. R1 has a loopback interface with IP 192.168.1.1/32 advertised into OSPF. R2 learns this route as an intra-area route (AD 110). R2 also runs RIP and learns the same prefix from R3 with AD 120. R2's 'show ip route 192.168.1.1' shows the RIP route. What is the root cause?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip route 192.168.1.0 255.255.255.0 Routing entry for 192.168.1.0/24 Known via "eigrp 100", distance 170, metric 30720, type internal Redistributing via eigrp 100 Last update from 10.1.1.2 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 10.1.1.2, from 10.1.1.2, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 30720, traffic share count is 1 Total delay is 2000 microseconds, minimum bandwidth is 100000 Kbit Reporting 1 hops What does this output indicate?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# debug ip routing IP routing debugging is on *Mar 1 00:01:23.456: RT: add 192.168.2.0/24 via 10.1.1.2, eigrp metric [170/30720] *Mar 1 00:01:23.456: RT: closer admin distance for 192.168.2.0, adding to routing table *Mar 1 00:01:23.456: RT: add 192.168.2.0/24 via 10.1.1.2, ospf metric [110/20] *Mar 1 00:01:23.456: RT: not add 192.168.2.0/24 via 10.1.1.2, ospf metric [110/20] - route already in table with better admin distance What does this output indicate?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip eigrp topology 192.168.3.0/24 all-links IP-EIGRP (AS 100): Topology entry for 192.168.3.0/24 State is Passive, Query origin flag is 1, 1 Successor(s), FD is 30720 Routing Descriptor Blocks: 10.1.1.2 (GigabitEthernet0/0), from 10.1.1.2, Send flag is 0x0 Composite metric is (30720/28160), Route is Internal Vector metric: Minimum bandwidth is 100000 Kbit Total delay is 2000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 1 10.1.2.2 (GigabitEthernet0/1), from 10.1.2.2, Send flag is 0x0 Composite metric is (30720/28160), Route is Internal Vector metric: Minimum bandwidth is 100000 Kbit Total delay is 2000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 1 What does this output indicate?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip ospf interface detail GigabitEthernet0/0 GigabitEthernet0/0 is up, line protocol is up Internet Address 10.1.1.1/24, Area 0, Attached via Network Statement Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 Topology-MTID Cost Disabled Shutdown Topology Name 0 1 no no Base Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 1.1.1.1, Interface address 10.1.1.1 Backup Designated router (ID) 2.2.2.2, Interface address 10.1.1.2 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:03 Supports Link-local Signaling (LLS) Cisco NSF helper support enabled IETF NSF helper support enabled Can be protected by per-prefix Loop-Free Fast Reroute Can be used for per-prefix Loop-Free Fast Reroute remote-LFA tunnels Index 1/1/1, flood queue length 0 Next 0x0(0)/0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 2.2.2.2 (Backup Designated Router) Suppress hello for 0 neighbor(s) What does this output indicate?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show bgp ipv4 unicast 192.168.4.0/24 BGP routing table entry for 192.168.4.0/24, version 2 Paths: (1 available, best #1, table default) Advertised to update-groups: 1 Refresh Epoch 1 Local 10.1.1.2 from 10.1.1.2 (2.2.2.2) Origin IGP, metric 0, localpref 100, valid, external, best rx pathid: 0, tx pathid: 0x0 What does this output indicate?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip route summary Route Source Networks Subnets Overhead Memory (bytes) connected 2 0 0 512 static 1 0 0 256 eigrp 100 3 0 0 768 ospf 1 2 0 0 512 bgp 65001 1 0 0 256 internal 1 0 0 256 Total 10 0 0 2560 What does this output indicate?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# debug eigrp packets EIGRP Packets debugging is on (UPDATE, REQUEST, QUERY, REPLY, HELLO, IPXSAP, PROBE, ACK, STUB, SIAQUERY, SIAREPLY) *Mar 1 00:01:23.456: EIGRP: received UPDATE on GigabitEthernet0/0 nbr 10.1.1.2 *Mar 1 00:01:23.456: AS 100, Flags 0x0, Seq 1/0 idbQ 0/0 iidbQ un/rely 0/0 *Mar 1 00:01:23.456: Int: 192.168.5.0/24, metric 30720/28160 *Mar 1 00:01:23.456: EIGRP: Enqueueing UPDATE on GigabitEthernet0/0 nbr 10.1.1.2 iidbQ un/rely 0/1 peerQ un/rely 0/0 serno 1-1 What does this output indicate?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip route 10.0.0.0 255.0.0.0 Routing entry for 10.0.0.0/8 Known via "static", distance 1, metric 0 Redistributing via eigrp 100 Last update from 10.1.1.2 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 10.1.1.2, from 10.1.1.2, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 0, traffic share count is 1 What does this output indicate?

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip route 172.16.0.0 255.255.0.0 Routing entry for 172.16.0.0/16 Known via "ospf 1", distance 110, metric 20, type intra area Last update from 10.1.1.2 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 10.1.1.2, from 2.2.2.2, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 20, traffic share count is 1 What does this output indicate?

What is the default administrative distance for a route learned via the Enhanced Interior Gateway Routing Protocol (EIGRP) summary route?

Which default administrative distance is assigned to routes learned via the Open Shortest Path First (OSPF) protocol?

What is the default administrative distance for a route learned via the Routing Information Protocol (RIP)?

What is the default administrative distance for a route learned via the Border Gateway Protocol (BGP) from an external peer (eBGP)?

What is the default administrative distance for a route learned via the Intermediate System-to-Intermediate System (IS-IS) protocol?

Which default administrative distance is assigned to a directly connected interface route?

What is the default administrative distance for a static route pointing to an interface (e.g., 'ip route 10.0.0.0 255.0.0.0 GigabitEthernet0/1')?

What is the default administrative distance for a route learned via the Routing Information Protocol next generation (RIPng)?

Which statement about administrative distance is true regarding the selection of routes in a routing table?

Drag and drop the steps to troubleshoot suboptimal routing due to incorrect Administrative Distance values into the correct order, from first to last.

Drag and drop the steps to troubleshoot Administrative Distance adjacency or connectivity failures into the correct order, from first to last.

Drag and drop the steps to verify and validate the Administrative Distance operational state into the correct order, from first to last.

Which TWO statements about the behavior of administrative distance in Cisco IOS are correct? (Choose TWO.)

An engineer wants to ensure that OSPF-learned routes are preferred over EIGRP-learned routes for a specific destination prefix, without affecting other routes. Which TWO actions will accomplish this? (Choose TWO.)

Which TWO statements about the interaction between administrative distance and floating static routes are true? (Choose TWO.)

Which TWO statements about the default administrative distances for different route sources are correct? (Choose TWO.)

Which TWO statements about the 'distance' command in Cisco IOS routing protocols are true? (Choose TWO.)

An engineer configures OSPF on two routers connected via a serial link. The MTU on one side is 1500 and on the other is 1400. The OSPF adjacency forms but stays stuck in EXSTART state. Which is the most likely explanation?

An engineer configures EIGRP named mode with an offset-list that increases the metric of a route on Router A. The route is still selected as the best path on Router A's neighbor, Router B, because Router B learns the same prefix via another EIGRP neighbor with a higher metric. Which is the most likely explanation?

An engineer configures iBGP between two routers in the same AS. The routes learned via iBGP are not being installed in the routing table, even though the next-hop is reachable. The IGP is OSPF and the routes are present in the BGP table. Which is the most likely explanation?

An engineer configures mutual redistribution between OSPF and EIGRP on a router. After a few minutes, the router's CPU spikes and routing loops occur. Which is the most likely explanation?

An engineer configures a DMVPN Phase 2 network. Spoke routers can communicate with the hub, but spoke-to-spoke tunnels do not form. The NHRP registration is successful, and the hub has the spoke's NBMA address. Which is the most likely explanation?

An engineer configures IPsec between two routers using a site-to-site VPN. The tunnel does not come up, and the debug output shows 'received unexpected payload type'. Both routers are configured with pre-shared keys. Which is the most likely explanation?

An engineer applies a Control Plane Policing (CoPP) policy to a router. After applying, the router becomes unreachable via SSH and SNMP, even though the policy allows management traffic. Which is the most likely explanation?

An engineer enables uRPF (strict mode) on an interface facing the Internet. Legitimate traffic from a customer network is being dropped. The customer network uses asymmetric routing where return traffic takes a different path. Which is the most likely explanation?

An engineer configures route redistribution from EIGRP into OSPF. The redistributed routes appear in the OSPF database but are not installed in the routing table of other OSPF routers. Which is the most likely explanation?