DEVICE: CORE - ROUTER CORE#SHOW RUN Building configuration... Current configuration : 4269 bytes ! ! Last configuration change at 11:26:36 UTC Mon May 11 2026 ! version 17.6 service timestamps debug datetime msec service timestamps log datetime msec platform qfp utilization monitor load 80 platform punt-keepalive disable-kernel-core ! hostname CORE ! boot-start-marker boot-end-marker ! ! ! no aaa new-model ! ! ! ! ! ! ! no ip domain lookup ! ! ! login on-success log ! ! ! ! ! ! ! subscriber templating multilink bundle-name authenticated ! ! ! crypto pki trustpoint TP-self-signed-3998722094 enrollment selfsigned subject-name cn=IOS-Self-Signed-Certificate-3998722094 revocation-check none rsakeypair TP-self-signed-3998722094 ! ! crypto pki certificate chain TP-self-signed-3998722094 certificate self-signed 01 30820330 30820218 A0030201 02020101 300D0609 2A864886 F70D0101 05050030 31312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274 69666963 6174652D 33393938 37323230 3934301E 170D3236 30353131 30383235 33365A17 0D333630 35313030 38323533 365A3031 312F302D 06035504 03132649 4F532D53 656C662D 5369676E 65642D43 65727469 66696361 74652D33 39393837 32323039 34308201 22300D06 092A8648 86F70D01 01010500 0382010F 00308201 0A028201 0100AD31 CB5D2C0D 0585D8E2 5AF74B04 1D0906A3 0BFCDE7A CACD48E1 D519AF86 F7E4C906 9701FF33 5B603E96 C627E604 B1637785 6D1A174F B230947D 32DF1A30 D8019489 1E586867 D4F98616 6B7B4411 96BD00D3 EA06F0C3 F3A29277 1BC67572 33A31F65 9D83358A DBD24CFF 7E39F3DE FF8DF810 2D34A892 E66BB772 F1362928 53FF1397 84140DDE 2D9C08FF 80B7F3F1 2673EDDB 450E8508 FFAF9F0A 09C9F953 2785D85D B7609344 A80F2E8A 532D4F01 7B458F4D 5D3C201C 0C242F2E 388DA3DA 82C58AB0 A75D5FDE 204B108C 953DF719 03CD71AB 0FA39C0E 0774E875 027AC5BA AF502E75 0A399DF0 4F872094 02DBE634 067707BE 92121C8E 1AE2C5BB B7391859 ED7B0203 010001A3 53305130 0F060355 1D130101 FF040530 030101FF 301F0603 551D2304 18301680 14DD8703 71835F8B F1BB3A41 91CD12D2 81795DC9 0D301D06 03551D0E 04160414 DD870371 835F8BF1 BB3A4191 CD12D281 795DC90D 300D0609 2A864886 F70D0101 05050003 82010100 7F3602DE 31765B09 64E4499C 38D48D6E FA4BBF52 FA739F0B 5508DB28 582256C2 2B87153C C08775AD 247A3A90 23846C8E B3F46285 A5A0C837 3DE1143B 6E1F4F20 72EFEFD2 E8EC3259 45026103 506F93DC 514FD9DA 48E288F4 53D73170 BC454546 71B60F3E 0FA40355 EFC03C18 922E69D3 BBDFC6F5 DA9E6D04 930672A8 3BB81E9C F8B3AC95 8BCDD3CB 52A0E4D1 55C53A86 A7E76291 E6028394 F97266E3 07D5CBA6 66CD2CEA 3ED9C32D 4EB90F66 0E8F834C 998001E6 683B636F FD9E9EF1 FD323634 CADE6043 7C5C19B0 CDE8E662 13E9281B D7A36394 ABC6DDAC 26018679 DD45BE8F 4AC2553B 5BF2111A E2CBD248 9DEBE11D C7D6AA02 94CAE8A1 9D8806DC 10D67CC8 quit ! ! license udi pid C8200L-1N-4T sn FGL2725L1P2 memory free low-watermark processor 67482 ! diagnostic bootup level minimal ! spanning-tree extend system-id ! ! redundancy mode none ! ! no cdp run ! lldp run ! ! ! ! ! interface Loopback1 description loopback1 ip address 172.16.20.129 255.255.255.192 ip ospf network point-to-point ! interface Loopback2 description loopback2 ip address 172.16.20.193 255.255.255.224 ! interface GigabitEthernet0/0/0 description CORE to BRANCH ip address 172.16.20.225 255.255.255.252 ip ospf dead-interval 120 ip ospf hello-interval 30 negotiation auto ! interface GigabitEthernet0/0/1 description CORE to SWITCH1 ip address 172.16.20.1 255.255.255.128 negotiation auto no lldp transmit ! interface GigabitEthernet0/0/2 no ip address negotiation auto ! interface GigabitEthernet0/0/3 no ip address negotiation auto ! interface Serial0/1/0 no ip address ip ospf dead-interval 120 ip ospf hello-interval 30 ! interface Serial0/1/1 no ip address ip ospf dead-interval 120 ip ospf hello-interval 30 ! router ospf 10 router-id 1.1.1.1 passive-interface GigabitEthernet0/0/1 passive-interface Loopback1 passive-interface Loopback2 network 172.16.20.0 0.0.0.127 area 0 network 172.16.20.128 0.0.0.63 area 0 network 172.16.20.192 0.0.0.31 area 0 network 172.16.20.224 0.0.0.3 area 0 ! ip http server ip http authentication local ip http secure-server ip forward-protocol nd ! ! ! ! ! ! control-plane ! ! line con 0 stopbits 1 line aux 0 line vty 0 4 login transport input ssh line vty 5 14 login transport input ssh ! ntp master 1 ! ! ! ! ! ! end CORE#SHOW IP INT BRIEF Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0/0 172.16.20.225 YES manual up up GigabitEthernet0/0/1 172.16.20.1 YES manual up up GigabitEthernet0/0/2 unassigned YES unset down down GigabitEthernet0/0/3 unassigned YES unset down down Serial0/1/0 unassigned YES unset down down Serial0/1/1 unassigned YES unset down down Loopback1 172.16.20.129 YES manual up up Loopback2 172.16.20.193 YES manual up up CORE#SHOW IP PROTOCOLS *** IP Routing is NSF aware *** Routing Protocol is "application" Sending updates every 0 seconds Invalid after 0 seconds, hold down 0, flushed after 0 Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Maximum path: 32 Routing for Networks: Routing Information Sources: Gateway Distance Last Update Distance: (default is 4) Routing Protocol is "ospf 10" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 1.1.1.1 Number of areas in this router is 1. 1 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: 172.16.20.0 0.0.0.127 area 0 172.16.20.128 0.0.0.63 area 0 172.16.20.192 0.0.0.31 area 0 172.16.20.224 0.0.0.3 area 0 Passive Interface(s): GigabitEthernet0/0/1 Loopback1 Loopback2 Routing Information Sources: Gateway Distance Last Update 2.2.2.2 110 00:37:40 Distance: (default is 110) CORE#SHOW IP ROUTE Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, m - OMP n - NAT, Ni - NAT inside, No - NAT outside, Nd - NAT DIA i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route H - NHRP, G - NHRP registered, g - NHRP registration summary o - ODR, P - periodic downloaded static route, l - LISP a - application route + - replicated route, % - next hop override, p - overrides from PfR & - replicated local route overrides by connected Gateway of last resort is 172.16.20.226 to network 0.0.0.0 O*E2 0.0.0.0/0 [110/1] via 172.16.20.226, 00:38:06, GigabitEthernet0/0/0 8.0.0.0/24 is subnetted, 1 subnets O IA 8.8.8.0 [110/2] via 172.16.20.226, 00:41:42, GigabitEthernet0/0/0 172.16.0.0/16 is variably subnetted, 8 subnets, 5 masks C 172.16.20.0/25 is directly connected, GigabitEthernet0/0/1 L 172.16.20.1/32 is directly connected, GigabitEthernet0/0/1 C 172.16.20.128/26 is directly connected, Loopback1 L 172.16.20.129/32 is directly connected, Loopback1 C 172.16.20.192/27 is directly connected, Loopback2 L 172.16.20.193/32 is directly connected, Loopback2 C 172.16.20.224/30 is directly connected, GigabitEthernet0/0/0 L 172.16.20.225/32 is directly connected, GigabitEthernet0/0/0