ospf  配置stub 区域，和 total-stub 区域。 zhangxinwen 发表于 2007-8-29 12:17:17

配置stub 区域，和 total-stub 区域。 R1# sh run interface Serial2/1  ip address 12.0.0.1 255.255.255.0 router ospf 100 network 12.0.0.0 0.0.0.255 area 12 R2# sh run interface Serial2/1  ip address 12.0.0.2 255.255.255.0 interface Serial2/2  ip address 23.0.0.2 255.255.255.0 router ospf 100 network 12.0.0.0 0.0.0.255 area 12  network 23.0.0.0 0.0.0.255 area 0 R3# sh run interface Serial2/1  ip address 23.0.0.3 255.255.255.0 interface Serial2/2  ip address 34.0.0.3 255.255.255.0 router ospf 100 network 23.0.0.0 0.0.0.255 area 0  network 34.0.0.0 0.0.0.255 area 34 R4# sh run interface Serial2/1  ip address 34.0.0.4 255.255.255.0 router ospf 34  network 34.0.0.0 0.0.0.255 area 34 ------------------------------------------------------------------------\ R1(config-router)#int lo0 R1(config-if)#ip add 1.1.1.1 255.255.255.0 R1(config-if)#router ospf 100 R1(config-router)#redistribute connected subnets   将直连重分布进ospf 进程中。 R4(config-router)#do sh ip ospf nei   Neighbor ID     Pri   State           Dead Time   Address         Interface 34.0.0.3          1   FULL/  -        00:00:34    34.0.0.3        Serial2/1 邻居建立起来了。 R4(config-router)#do sh ip ospf data          OSPF Router with ID (34.0.0.4) (Process ID 34)                     Router Link States (Area 34)   Link ID         ADV Router      Age         Seq#       Checksum Link count 34.0.0.3        34.0.0.3        49          0x8000000E 0x00518D 2 34.0.0.4        34.0.0.4        48          0x8000000E 0x00429B 2                   Summary Net Link States (Area 34)   Link ID         ADV Router      Age         Seq#       Checksum 12.0.0.0        34.0.0.3        58          0x80000004 0x00A6E1 23.0.0.0        34.0.0.3        58          0x80000004 0x009429                   Summary ASB Link States (Area 34)   Link ID         ADV Router      Age         Seq#       Checksum 12.0.0.1        34.0.0.3        58          0x80000001 0x0094F4                   Type-5 AS External Link States   Link ID         ADV Router      Age         Seq#       Checksum Tag 1.1.1.0         12.0.0.1        1683        0x80000001 0x00513F 0 查看R4数据库，有1，3 ，4，5 型LSA. 因为2型LSA.是由广播型网络的 DR,或BDR 产生，在本实验使用的是点到点链路，所以没有2型LSA.。 R4(config-router)#do sh ip rout Gateway of last resort is not set        34.0.0.0/24 is subnetted, 1 subnets C       34.0.0.0 is directly connected, Serial2/1      1.0.0.0/24 is subnetted, 1 subnets O E2    1.1.1.0 [110/20] via 34.0.0.3, 00:06:16, Serial2/1      23.0.0.0/24 is subnetted, 1 subnets O IA    23.0.0.0 [110/128] via 34.0.0.3, 00:16:27, Serial2/1      12.0.0.0/24 is subnetted, 1 subnets O IA    12.0.0.0 [110/192] via 34.0.0.3, 00:16:27, Serial2/1 R3(config-router)#area 34 stub R4(config-router)#area 34 stub 将区域34 的路由器全部配置为stub区域。 R3(config-router)#do sh ip rou Gateway of last resort is not set        34.0.0.0/24 is subnetted, 1 subnets C       34.0.0.0 is directly connected, Serial2/2      1.0.0.0/24 is subnetted, 1 subnets O E2    1.1.1.0 [110/20] via 23.0.0.2, 00:07:58, Serial2/1      23.0.0.0/24 is subnetted, 1 subnets C       23.0.0.0 is directly connected, Serial2/1      12.0.0.0/24 is subnetted, 1 subnets O IA    12.0.0.0 [110/128] via 23.0.0.2, 00:07:58, Serial2/1 R3路由表和配置stub区域前一样没有变、 R4(config-router)#do sh ip ospf da          OSPF Router with ID (34.0.0.4) (Process ID 34)                     Router Link States (Area 34)   Link ID         ADV Router      Age         Seq#       Checksum Link count 34.0.0.3        34.0.0.3        1017        0x8000000C 0x00736F 2 34.0.0.4        34.0.0.4        1017        0x8000000C 0x00647D 2                   Summary Net Link States (Area 34)   Link ID         ADV Router      Age         Seq#       Checksum 0.0.0.0         34.0.0.3        1037        0x80000001 0x006CAC 12.0.0.0        34.0.0.3        1037        0x80000003 0x00C6C4 23.0.0.0        34.0.0.3        1037        0x80000003 0x00B40C 查看R4数据库，现在只有1，3 型LSA.。并且多了一条3型的默认路由 R4(config-router)#do sh ip rou Gateway of last resort is 34.0.0.3 to network 0.0.0.0        34.0.0.0/24 is subnetted, 1 subnets C       34.0.0.0 is directly connected, Serial2/1      23.0.0.0/24 is subnetted, 1 subnets O IA    23.0.0.0 [110/128] via 34.0.0.3, 00:00:21, Serial2/1      12.0.0.0/24 is subnetted, 1 subnets O IA    12.0.0.0 [110/192] via 34.0.0.3, 00:00:21, Serial2/1 O*IA 0.0.0.0/0 [110/65] via 34.0.0.3, 00:00:21, Serial2/1 查看R4路由表。此时路由表中没有了重分布进来的外部路由。多了一条3型的默认路由。结论：stub（末节区域）区域的路由器，不接收 那些关于本自治系统外的路由信息。只有域间域内的路由，lsa 1，lsa 2，lsa 3，过滤lsa 4，lsa 5，ABR向本区域的路由器产生默认路由。 R3(config-router)#area 34 stub no-summary   将区域34配置为total-stub区域。只需在ABR 上做就可以了。 R4(config-router)#do sh ip ospf da        OSPF Router with ID (34.0.0.4) (Process ID 34)                 Router Link States (Area 34)   Link ID         ADV Router      Age         Seq#       Checksum Link count 34.0.0.3        34.0.0.3        148         0x80000012 0x006775 2 34.0.0.4        34.0.0.4        189         0x80000010 0x005C81 2                   Summary Net Link States (Area 34)   Link ID         ADV Router      Age         Seq#       Checksum 0.0.0.0         34.0.0.3        149         0x80000002 0x006AAD 查看R4数据库，现在只有1，默认3 型LSA.。 R4(config-router)#do sh ip rout Gateway of last resort is 34.0.0.3 to network 0.0.0.0        34.0.0.0/24 is subnetted, 1 subnets C       34.0.0.0 is directly connected, Serial2/1 O*IA 0.0.0.0/0 [110/65] via 34.0.0.3, 00:04:33, Serial2/1 查看R4路由表。将34区域配置为total-stub区域后。路由表中只有直连路由和一条默认路由。 结论：total-stub（完全末节区域）区域不接收外部自治系统路由或来自本自治系统内其他区域的汇总路由，过滤了4，5型和其他3型，只有1，2型和默认3型LSA. 阅读全文 | 回复 | 引用通告

ospf stub  区域lsa类型 zhangxinwen 发表于 2007-8-27 18:06:36

实验目的：验证stub区域的LSA. 类型         区域间汇总和区域外汇总 R1(config-router)#do sh run interface Loopback0  ip address 192.168.16.1 255.255.255.0 interface Loopback1  ip address 192.168.17.1 255.255.255.0 interface Loopback2  ip address 192.168.18.1 255.255.255.0 interface Loopback3  ip address 192.168.19.1 255.255.255.0 interface Serial2/1  ip address 12.0.0.1 255.255.255.0 router ospf 100  router-id 1.1.1.1  network 12.0.0.0 0.0.0.255 area 12  network 192.168.16.0 0.0.3.255 area 12 !       R2(config-router)#do sh run interface Loopback0  ip address 2.2.2.2 255.255.255.0 interface Serial2/1  ip address 12.0.0.2 255.255.255.0 interface Serial2/2  ip address 23.0.0.2 255.255.255.0 router ospf 100  router-id 2.2.2.2 area 12 range 192.168.16.0 255.255.252.0   在ABR上做域间汇总  network 12.0.0.0 0.0.0.255 area 12  network 23.0.0.0 0.0.0.255 area 0  R3(config-router)# do sh run interface Serial2/1  ip address 23.0.0.3 255.255.255.0 interface Serial2/2  ip address 34.0.0.3 255.255.255.0 router ospf 100  router-id 3.3.3.3  network 23.0.0.0 0.0.0.255 area 0  network 34.0.0.0 0.0.0.255 area 34  R4#sh run interface Loopback0  ip address 150.100.32.1 255.255.255.0 interface Loopback1  ip address 150.100.33.1 255.255.255.0 interface Loopback2  ip address 150.100.34.1 255.255.255.0 interface Serial2/1  ip address 34.0.0.4 255.255.255.0 router ospf 100  router-id 4.4.4.4 summary-address 150.100.32.0 255.255.252.0  在ASBR上汇总自治系统外部路由。 redistribute connected subnets   直连重分布到ospf 进程 network 34.0.0.0 0.0.0.255 area 34 --------------------------------------------------------------------------------------------------------------------\ R2(config-if)#do sh ip rout Gateway of last resort is not set      34.0.0.0/24 is subnetted, 1 subnets O IA    34.0.0.0 [110/128] via 23.0.0.3, 00:01:35, Serial2/2      2.0.0.0/24 is subnetted, 1 subnets C       2.2.2.0 is directly connected, Loopback0      23.0.0.0/24 is subnetted, 1 subnets C       23.0.0.0 is directly connected, Serial2/2      192.168.17.0/32 is subnetted, 1 subnets O       192.168.17.1 [110/65] via 12.0.0.1, 00:01:35, Serial2/1      12.0.0.0/24 is subnetted, 1 subnets C       12.0.0.0 is directly connected, Serial2/1      192.168.16.0/32 is subnetted, 1 subnets O       192.168.16.1 [110/65] via 12.0.0.1, 00:01:35, Serial2/1      192.168.19.0/32 is subnetted, 1 subnets O       192.168.19.1 [110/65] via 12.0.0.1, 00:01:36, Serial2/1      150.100.0.0/22 is subnetted, 1 subnets O E2    150.100.32.0 [110/20] via 23.0.0.3, 00:01:36, Serial2/2      192.168.18.0/32 is subnetted, 1 subnets O       192.168.18.1 [110/65] via 12.0.0.1, 00:01:36, Serial2/1 O    192.168.16.0/22 is a summary, 00:01:37, Null0 在ABR（R2）上做域间汇总，会多出一条到null 0的路由。用于防止过大宣告所引起的路由黑洞。 R3(config-if)#do sh ip rou Gateway of last resort is not set      34.0.0.0/24 is subnetted, 1 subnets C       34.0.0.0 is directly connected, Serial2/2      3.0.0.0/24 is subnetted, 1 subnets C       3.3.3.0 is directly connected, Loopback0      23.0.0.0/24 is subnetted, 1 subnets C       23.0.0.0 is directly connected, Serial2/1      12.0.0.0/24 is subnetted, 1 subnets O IA    12.0.0.0 [110/128] via 23.0.0.2, 00:12:14, Serial2/1      150.100.0.0/22 is subnetted, 1 subnets O E2    150.100.32.0 [110/20] via 34.0.0.4, 00:04:04, Serial2/2 O IA 192.168.16.0/22 [110/129] via 23.0.0.2, 00:04:09, Serial2/1 经过域间和域外汇总，在R3上就会是会总后的路由。150.100.0.0/22 ，192.168.16.0/22 R4(config)#do sh ip rou Gateway of last resort is not set      34.0.0.0/24 is subnetted, 1 subnets C       34.0.0.0 is directly connected, Serial2/1      23.0.0.0/24 is subnetted, 1 subnets O IA    23.0.0.0 [110/128] via 34.0.0.3, 00:10:36, Serial2/1      12.0.0.0/24 is subnetted, 1 subnets O IA    12.0.0.0 [110/192] via 34.0.0.3, 00:10:36, Serial2/1      150.100.0.0/16 is variably subnetted, 4 subnets, 2 masks C       150.100.34.0/24 is directly connected, Loopback2 O       150.100.32.0/22 is a summary, 00:09:36, Null0 C       150.100.32.0/24 is directly connected, Loopback0 C       150.100.33.0/24 is directly connected, Loopback1 O IA 192.168.16.0/22 [110/193] via 34.0.0.3, 00:02:31, Serial2/1 域外汇总对自己不起作用，，只是通告给别人减少了路由条目。自己也多了一条到null 0的路由。用于防止过大宣告所引起的路由黑洞。 R1(config-router)#do sh ip ospf da        OSPF Router with ID (192.168.19.1) (Process ID 100)                 Router Link States (Area 12) Link ID         ADV Router      Age         Seq#       Checksum Link count 2.2.2.2         2.2.2.2         38          0x80000013 0x005297 2 192.168.19.1    192.168.19.1    38          0x80000014 0x00BA86 6                 Summary Net Link States (Area 12) Link ID         ADV Router      Age         Seq#       Checksum 23.0.0.0        2.2.2.2         55          0x8000000A 0x009143 34.0.0.0        2.2.2.2         55          0x80000007 0x008A02                 Summary ASB Link States (Area 12) Link ID         ADV Router      Age         Seq#       Checksum 4.4.4.4         2.2.2.2         55          0x80000001 0x008B18                 Type-5 AS External Link States Link ID         ADV Router      Age         Seq#       Checksum Tag 150.100.32.0    4.4.4.4         1729        0x80000002 0x00A2D4 0      查看R1数据库，  在区域12中有1型，3型。4型 ，5型  LSA. R2(config-router)# do sh ip ospf da        OSPF Router with ID (2.2.2.2) (Process ID 100)                 Router Link States (Area 0) Link ID         ADV Router      Age         Seq#       Checksum Link count 2.2.2.2         2.2.2.2         1705        0x8000000E 0x00CD7C 2 3.3.3.3         3.3.3.3         1599        0x80000008 0x0079D1 2                 Summary Net Link States (Area 0) Link ID         ADV Router      Age         Seq#       Checksum 12.0.0.0        2.2.2.2         940         0x80000005 0x002BB9 34.0.0.0        3.3.3.3         1599        0x80000005 0x00EDDC 34.0.0.0        4.4.4.4         3718        0x80000002 0x00D5F3                 Summary ASB Link States (Area 0) Link ID         ADV Router      Age         Seq#       Checksum 4.4.4.4         3.3.3.3         1599        0x80000002 0x00E8F5                 Router Link States (Area 12)           Link ID         ADV Router      Age         Seq#       Checksum Link count 2.2.2.2         2.2.2.2         148         0x80000014 0x0006BC 1 192.168.19.1    192.168.19.1    231         0x80000014 0x00BA86 6                 Summary Net Link States (Area 12) Link ID         ADV Router      Age         Seq#       Checksum 23.0.0.0        2.2.2.2         248         0x8000000A 0x009143 34.0.0.0        2.2.2.2         248         0x80000007 0x008A02                 Summary ASB Link States (Area 12) Link ID         ADV Router      Age         Seq#       Checksum 4.4.4.4         2.2.2.2         248         0x80000001 0x008B18                 Type-5 AS External Link States Link ID         ADV Router      Age         Seq#       Checksum Tag 150.100.32.0    4.4.4.4         1923        0x80000002 0x00A2D4 0 查看R2数据库，  在区域0中有1型，3型。4型 ，5型，  LSA. 在区域12中有1型，3型。4型 ，5型  LSA. R1(config-router)#area 12 stub   将区域12 的所有路由器都配置成stub R2(config-router)#area 12 stub R1(config-router)#do sh ip ospf da        OSPF Router with ID (192.168.19.1) (Process ID 100)                 Router Link States (Area 12) Link ID         ADV Router      Age         Seq#       Checksum Link count 2.2.2.2         2.2.2.2         10          0x80000011 0x007479 2 192.168.19.1    192.168.19.1    10          0x80000012 0x00DC68 6                 Summary Net Link States (Area 12) Link ID         ADV Router      Age         Seq#       Checksum 0.0.0.0         2.2.2.2         41          0x80000001 0x0075C0 23.0.0.0        2.2.2.2         41          0x80000009 0x00B126 34.0.0.0        2.2.2.2         41          0x80000006 0x00AAE4 配置成stub后查看R1数据库，  在区域12中有1型，3型,LSA.。 R1(config-router)#do sh ip rou Gateway of last resort is 12.0.0.2 to network 0.0.0.0      34.0.0.0/24 is subnetted, 1 subnets O IA    34.0.0.0 [110/192] via 12.0.0.2, 00:03:31, Serial2/1      23.0.0.0/24 is subnetted, 1 subnets O IA    23.0.0.0 [110/128] via 12.0.0.2, 00:03:31, Serial2/1 C    192.168.17.0/24 is directly connected, Loopback1      12.0.0.0/24 is subnetted, 1 subnets C       12.0.0.0 is directly connected, Serial2/1 C    192.168.16.0/24 is directly connected, Loopback0 C    192.168.19.0/24 is directly connected, Loopback3 C    192.168.18.0/24 is directly connected, Loopback2 O*IA 0.0.0.0/0 [110/65] via 12.0.0.2, 00:03:31, Serial2/1 且3型的,LSA.多了一条默认路由。 R2(config-router)#do sh ip ospf da        OSPF Router with ID (2.2.2.2) (Process ID 100)                 Router Link States (Area 0) Link ID         ADV Router      Age         Seq#       Checksum Link count 2.2.2.2         2.2.2.2         409         0x8000000F 0x00CB7D 2 3.3.3.3         3.3.3.3         291         0x80000009 0x0077D2 2                 Summary Net Link States (Area 0) Link ID         ADV Router      Age         Seq#       Checksum 12.0.0.0        2.2.2.2         1645        0x80000005 0x002BB9 34.0.0.0        3.3.3.3         291         0x80000006 0x00EBDD 192.168.16.0    2.2.2.2         269         0x80000001 0x006815                 Summary ASB Link States (Area 0) Link ID         ADV Router      Age         Seq#       Checksum 4.4.4.4         3.3.3.3         291         0x80000003 0x00E6F6                 Router Link States (Area 12)           Link ID         ADV Router      Age         Seq#       Checksum Link count 2.2.2.2         2.2.2.2         283         0x80000015 0x006C7D 2 192.168.19.1    192.168.19.1    283         0x80000016 0x00D46C 6                 Summary Net Link States (Area 12) Link ID         ADV Router      Age         Seq#       Checksum 0.0.0.0         2.2.2.2         290         0x80000001 0x0075C0 23.0.0.0        2.2.2.2         290         0x8000000B 0x00AD28 34.0.0.0        2.2.2.2         290         0x80000008 0x00A6E6                 Type-5 AS External Link States Link ID         ADV Router      Age         Seq#       Checksum Tag 150.100.32.0    4.4.4.4         634         0x80000003 0x00A0D5 0 配置成stub区域后，查看R2数据库，  在区域0中有1型，3型。4型，5型 ，LSA.没有变 在区域12中有1型，3型，LSA.。且3型的,LSA.多了一条默认路由。 R2(config-router)#do sh ip route Codes: C - connected, S - static, I - IGRP, 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, E - EGP        i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area        * - candidate default, U - per-user static route, o - ODR        P - periodic downloaded static route Gateway of last resort is not set      34.0.0.0/24 is subnetted, 1 subnets O IA    34.0.0.0 [110/128] via 23.0.0.3, 00:07:13, Serial2/2      2.0.0.0/24 is subnetted, 1 subnets C       2.2.2.0 is directly connected, Loopback0      23.0.0.0/24 is subnetted, 1 subnets C       23.0.0.0 is directly connected, Serial2/2      192.168.17.0/32 is subnetted, 1 subnets O       192.168.17.1 [110/65] via 12.0.0.1, 00:07:13, Serial2/1      12.0.0.0/24 is subnetted, 1 subnets C       12.0.0.0 is directly connected, Serial2/1      192.168.16.0/32 is subnetted, 1 subnets O       192.168.16.1 [110/65] via 12.0.0.1, 00:07:13, Serial2/1      192.168.19.0/32 is subnetted, 1 subnets O       192.168.19.1 [110/65] via 12.0.0.1, 00:07:14, Serial2/1      150.100.0.0/22 is subnetted, 1 subnets O E2    150.100.32.0 [110/20] via 23.0.0.3, 00:07:14, Serial2/2      192.168.18.0/32 is subnetted, 1 subnets O       192.168.18.1 [110/65] via 12.0.0.1, 00:07:14, Serial2/1 O    192.168.16.0/22 is a summary, 00:07:14, Null0 R2上没有默认路由。 结论stub区域的路由器会过滤类型4 和类型5的LSA.(既不需要外部路由)，此时会产生一条默认路由，3型LSA. 阅读全文 | 回复 | 引用通告

rip    修改度量 zhangxinwen 发表于 2007-8-23 14:03:10

实验目的：使用偏移列表offset-list修改metric值。使R3在正常情况下到网络1.0.0.0/8走Serial2/1，只有当使用这跳串形链路失败时，才使用这条快速以太链路。只想把这条快速以太链路作为备份链路 基本配置 R1#show running-config interface Loopback0  ip address 1.1.1.1 255.255.255.0 interface FastEthernet0/0  ip address 13.0.0.1 255.255.255.0 interface Serial2/1  ip address 12.0.0.1 255.255.255.0 router rip  network 12.0.0.0  network 13.0.0.0 network 1.0.0.0 R2#show running-config interface Serial2/1  ip address 12.0.0.2 255.255.255.0 interface Serial2/2  ip address 23.0.0.2 255.255.255.0 router rip  network 12.0.0.0  network 23.0.0.0 R3#show running-config interface FastEthernet0/0  ip address 13.0.0.3 255.255.255.0 interface Serial2/1  ip address 23.0.0.3 255.255.255.0 router rip  network 13.0.0.0  network 23.0.0.0 ------------------------------------------------------------------------------\ R3(config-router)# do sh ip rou Gateway of last resort is not set   R    1.0.0.0/8 [120/1] via 13.0.0.1, 00:00:02, FastEthernet0/0      23.0.0.0/24 is subnetted, 1 subnets C       23.0.0.0 is directly connected, Serial2/1 R    12.0.0.0/8 [120/1] via 23.0.0.2, 00:00:12, Serial2/1                 [120/1] via 13.0.0.1, 00:00:02, FastEthernet0/0      13.0.0.0/24 is subnetted, 1 subnets C       13.0.0.0 is directly connected, FastEthernet0/0 查看R3路由表，看到有1条到10.0.0/8 的路由,etric 1. R3(config-router)#int f0/0 R3(config-if)#shut R3(config-if)#do sh ip rou Gateway of last resort is not set   R    1.0.0.0/8 [120/2] via 23.0.0.2, 00:00:06, Serial2/1      23.0.0.0/24 is subnetted, 1 subnets C       23.0.0.0 is directly connected, Serial2/1 R    12.0.0.0/8 [120/1] via 23.0.0.2, 00:00:06, Serial2/1 R    13.0.0.0/8 [120/2] via 23.0.0.2, 00:00:06, Serial2/1 关闭f0/0接口后，此时路由表中到1.0.0./8的路由下一跳是R2。Metric值是2。 在正常情况下。依照rip 的特性，rip会选择跳数少的路径。在这不考滤链路带宽。 假设此题只想把这条快速以太链路作为备份链路，只有当经过R2失败时，才使用这条快速以太链路。 使用偏移列表，将R3经过F0/0到达1.0.0.0/8网络的Metric设为3跳。 R3(config)#access-list 1 permit 1.0.0.0  0.0.0.0 R3(config)#router rip R3(config-router)#offset-list 1 in 3 f0/0 R3(config-if)#int f0/0 R3(config-if)#no shut R3#debug ip rip RIP protocol debugging is on R3# 00:55:21: RIP: received v1 update from 13.0.0.1 on FastEthernet0/0 00:55:21:      1.0.0.0 in 4 hops 00:55:21:      12.0.0.0 in 1 hops R3# 00:55:27: RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (13.0.0.3) 00:55:27: RIP: build update entries 00:55:27:       network 1.0.0.0 metric 3 00:55:27:       network 23.0.0.0 metric 1 00:55:27: RIP: sending v1 update to 255.255.255.255 via Serial2/1 (23.0.0.3) 00:55:27: RIP: build update entries 00:55:27:       network 13.0.0.0 metric 1 R3# 00:55:40: RIP: received v1 update from 23.0.0.2 on Serial2/1 00:55:40:      1.0.0.0 in 2 hops 00:55:40:      12.0.0.0 in 1 hops 通过调试信息看到 R3接收的1.0.0.0的更新，从F0/0通告来的metric是3。   从S2/1通告来的metric是2。 说明偏移列表在起作用。   关闭s2/1接口，验证到网络1.0.0.0，在经过R2失败时，使用f0/0这条链路。 R3(config)#int s2/1 R3(config-if)#shut R3#sh ip rou Gateway of last resort is not set   R    1.0.0.0/8 [120/4] via 13.0.0.1, 00:00:08, FastEthernet0/0 R    12.0.0.0/8 [120/1] via 13.0.0.1, 00:00:08, FastEthernet0/0      13.0.0.0/24 is subnetted, 1 subnets C       13.0.0.0 is directly connected, FastEthernet0/0 实验成功。此时到网络1.0.0.0/8下一跳R1 。Metric是4 。 阅读全文 | 回复 | 引用通告

ping 127.x.x.x 为什么能通？ zhangxinwen 发表于 2007-8-20 16:37:53

ping 127.x.x.x 为什么能通？ 答：这是本机用于测试的 它是IP定义里留给系统内部网络测试通信的内部地址 两台电脑组网可不可以使用127.X.X.X 进行？ 不行，因为127.x.x.x 网段是用于内部网络测试的内部地址。    所以主机永远不会将这个地址发出去。 阅读全文 | 回复 | 引用通告

ping 127.x.x.x 为什么能通？ zhangxinwen 发表于 2007-8-20 16:37:53

ping 127.x.x.x 为什么能通？ 答：这是本机用于测试的 它是IP定义里留给系统内部网络测试通信的内部地址 两台电脑组网可不可以使用127.X.X.X 进行？ 不行，因为127.x.x.x 网段是用于内部网络测试的内部地址。    所以主机永远不会将这个地址发出去。 阅读全文 | 回复 | 引用通告