好久沒看網絡的東西，最近突然心血來潮，溫習一下BGP的路由協議，雖說這個協議企業裏面使用很少，但是總歸還是一個重要的協議，以下爲GNS3拓撲圖，其中R1/R2/R4爲C7200，其他的均爲3640
R1/R2/R3/R4運行基於OSPF的iBGP協議，R1與R5、R7之間，R4與R6、R8之間運行基於EIGRP的eBGP協議。
注意點如下，在配置裏面也做了標註
1、iBGP中運行的IGP協議需要通告所有的loopback接口的IP，否則iBGP鄰居無法建立
2、BGP中需要通告相關的接口IP路由，否則bgp路由表中無相關的BGP路由
3、eBGP不需要指定loopback口建立鄰居，直接使用物理接口
R1配置：
!
hostname R1
!
interface Loopback1
ip address 172.11.11.1 255.255.255.255
!
interface FastEthernet0/0
ip address 10.100.1.1 255.255.255.252
!
interface FastEthernet0/1
ip address 10.11.1.1 255.255.255.0
!
interface FastEthernet1/0
ip address 192.168.15.1 255.255.255.0
!
interface FastEthernet1/1
ip address 192.168.17.1 255.255.255.0
!
interface FastEthernet2/0
ip address 10.11.12.1 255.255.255.0
!
router eigrp 11
network 192.168.15.1 0.0.0.0
no auto-summary
!
router eigrp 12
network 192.168.17.1 0.0.0.0
no auto-summary
!
router ospf 1
log-adjacency-changes
network 10.11.1.0 0.0.0.255 area 0
network 10.11.12.0 0.0.0.255 area 0
network 10.100.1.0 0.0.0.3 area 0
network 172.11.11.1 0.0.0.0 area 0 iBGP中運行的IGP協議需要通告所有的loopback接口的IP，否則iBGP鄰居無法建立，R2/R3/R4同理
!
router bgp 65332
no synchronization
bgp log-neighbor-changes
network 10.11.1.0 mask 255.255.255.0 BGP中需要通告相關的接口IP路由，否則相關路由器信息僅會顯示在IGP路由表中，bgp路由表中無相關路由信息，其他所有路由器同理
network 10.11.12.0 mask 255.255.255.0
network 10.100.1.0 mask 255.255.255.252
network 172.11.11.1 mask 255.255.255.255
network 192.168.15.0
network 192.168.17.0
neighbor 172.11.11.3 remote-as 65332
neighbor 172.11.11.3 update-source Loopback1
neighbor 172.12.12.1 remote-as 65332
neighbor 172.12.12.1 update-source Loopback1
neighbor 172.12.12.4 remote-as 65332
neighbor 172.12.12.4 update-source Loopback1
neighbor 192.168.15.10 remote-as 65115
neighbor 192.168.15.10 ebgp-multihop 2
neighbor 192.168.15.10 update-source FastEthernet1/0
neighbor 192.168.17.10 remote-as 65117
neighbor 192.168.17.10 ebgp-multihop 2
neighbor 192.168.17.10 update-source FastEthernet1/1
no auto-summary
!
R2配置：
!
hostname R2
!
interface Loopback1
ip address 172.12.12.1 255.255.255.255
!
interface FastEthernet0/0
ip address 10.100.1.2 255.255.255.252
!
interface FastEthernet0/1
ip address 10.12.1.1 255.255.255.0
!
interface FastEthernet3/1
ip address 10.12.22.1 255.255.255.0
!
router ospf 1
log-adjacency-changes
network 10.12.1.0 0.0.0.255 area 0
network 10.12.22.0 0.0.0.255 area 0
network 10.100.1.0 0.0.0.3 area 0
network 172.12.12.1 0.0.0.0 area 0
!
router bgp 65332
no synchronization
bgp log-neighbor-changes
network 10.12.1.0 mask 255.255.255.0
network 10.12.22.0 mask 255.255.255.0
network 10.100.1.0 mask 255.255.255.252
network 172.12.12.1 mask 255.255.255.255
neighbor 172.11.11.1 remote-as 65332
neighbor 172.11.11.1 update-source Loopback1
neighbor 172.11.11.3 remote-as 65332
neighbor 172.11.11.3 update-source Loopback1
neighbor 172.12.12.4 remote-as 65332
neighbor 172.12.12.4 update-source Loopback1
no auto-summary
!
R3配置
!
hostname R3
!
interface Loopback11
ip address 172.11.11.3 255.255.255.255
!
interface FastEthernet0/0
ip address 10.11.1.2 255.255.255.0
!
interface FastEthernet1/0
ip address 10.101.1.1 255.255.255.252
!
interface FastEthernet2/0
ip address 10.12.22.2 255.255.255.0
!
router ospf 1
log-adjacency-changes
network 10.11.1.0 0.0.0.255 area 0
network 10.12.22.0 0.0.0.255 area 0
network 10.101.1.0 0.0.0.3 area 0
network 172.11.11.3 0.0.0.0 area 0
!
router bgp 65332
no synchronization
bgp log-neighbor-changes
network 10.11.1.0 mask 255.255.255.0
network 10.12.22.0 mask 255.255.255.0
network 10.101.1.0 mask 255.255.255.252
network 172.11.11.3 mask 255.255.255.255
neighbor 172.11.11.1 remote-as 65332
neighbor 172.11.11.1 update-source Loopback11
neighbor 172.12.12.1 remote-as 65332
neighbor 172.12.12.1 update-source Loopback11
neighbor 172.12.12.4 remote-as 65332
neighbor 172.12.12.4 update-source Loopback11
no auto-summary
!
R4配置
interface Loopback11
ip address 172.12.12.4 255.255.255.255
!
interface FastEthernet0/0
ip address 10.12.1.2 255.255.255.0
!
interface FastEthernet0/1
ip address 10.101.1.2 255.255.255.252
!
interface FastEthernet1/0
ip address 192.168.16.1 255.255.255.0
!
interface FastEthernet1/1
ip address 192.168.18.1 255.255.255.0
!
interface FastEthernet2/0
ip address 10.11.12.2 255.255.255.0
!
router eigrp 1
network 192.168.16.0
no auto-summary
!
router eigrp 2
network 192.168.18.0
no auto-summary
!
router ospf 11
log-adjacency-changes
network 10.11.12.0 0.0.0.255 area 0
network 10.12.1.0 0.0.0.255 area 0
network 10.101.1.0 0.0.0.3 area 0
network 172.12.12.4 0.0.0.0 area 0
!
router bgp 65332
no synchronization
bgp log-neighbor-changes
network 10.11.12.0 mask 255.255.255.0
network 10.12.1.0 mask 255.255.255.0
network 10.101.1.0 mask 255.255.255.252
network 172.12.12.4 mask 255.255.255.255
network 192.168.16.0
network 192.168.18.0
neighbor 172.11.11.1 remote-as 65332
neighbor 172.11.11.1 update-source Loopback11
neighbor 172.11.11.3 remote-as 65332
neighbor 172.11.11.3 update-source Loopback11
neighbor 172.12.12.1 remote-as 65332
neighbor 172.12.12.1 update-source Loopback11
neighbor 192.168.16.10 remote-as 65116
neighbor 192.168.16.10 ebgp-multihop 2
neighbor 192.168.16.10 update-source FastEthernet1/0
neighbor 192.168.18.10 remote-as 65118
neighbor 192.168.18.10 ebgp-multihop 2
neighbor 192.168.18.10 update-source FastEthernet1/1
no auto-summary
!
R5配置
interface FastEthernet0/0
ip address 192.168.15.10 255.255.255.0
!
router eigrp 11
network 192.168.15.10 0.0.0.0
no auto-summary
!
router bgp 65115
no synchronization
bgp log-neighbor-changes
network 192.168.15.0
neighbor 192.168.15.1 remote-as 65332
neighbor 192.168.15.1 ebgp-multihop 2
neighbor 192.168.15.1 update-source FastEthernet0/0
no auto-summary
R6配置
interface FastEthernet0/0
ip address 192.168.16.10 255.255.255.0
duplex auto
speed auto
!
router eigrp 1
network 192.168.16.0
auto-summary
!
router bgp 65116
no synchronization
bgp log-neighbor-changes
network 192.168.16.0
neighbor 192.168.16.1 remote-as 65332
neighbor 192.168.16.1 ebgp-multihop 2
neighbor 192.168.16.1 update-source FastEthernet0/0
no auto-summary
R7配置
interface FastEthernet0/0
ip address 192.168.17.10 255.255.255.0
!
router eigrp 12
network 192.168.17.10 0.0.0.0
no auto-summary
!
router bgp 65117
no synchronization
bgp log-neighbor-changes
network 192.168.17.0
neighbor 192.168.17.1 remote-as 65332
neighbor 192.168.17.1 ebgp-multihop 2
neighbor 192.168.17.1 update-source FastEthernet0/0
no auto-summary
R8配置
interface FastEthernet0/0
ip address 192.168.18.10 255.255.255.0
!
router eigrp 2
network 192.168.18.0
no auto-summary
!
router bgp 65118
no synchronization
bgp log-neighbor-changes
network 192.168.18.0
neighbor 192.168.18.1 remote-as 65332
neighbor 192.168.18.1 ebgp-multihop 2
neighbor 192.168.18.1 update-source FastEthernet0/0
no auto-summary
---------------------------------------------------------------------------
show命令如下：
---------------------------------------------------------------------------
R6#sh ip bgp
BGP table version is 353, local router ID is 192.168.16.10
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 10.11.1.0/24 192.168.16.1 0 65332 i
*> 10.11.12.0/24 192.168.16.1 0 0 65332 i
*> 10.12.1.0/24 192.168.16.1 0 0 65332 i
*> 10.12.22.0/24 192.168.16.1 0 65332 i
*> 10.100.1.0/30 192.168.16.1 0 65332 i
*> 10.101.1.0/30 192.168.16.1 0 0 65332 i
*> 172.11.11.1/32 192.168.16.1 0 65332 i
*> 172.11.11.3/32 192.168.16.1 0 65332 i
*> 172.12.12.1/32 192.168.16.1 0 65332 i
*> 172.12.12.4/32 192.168.16.1 0 0 65332 i
*> 192.168.15.0 192.168.16.1 0 65332 i
* 192.168.16.0 192.168.16.1 0 0 65332 i
*> 0.0.0.0 0 32768 i
*> 192.168.17.0 192.168.16.1 0 65332 i
*> 192.168.18.0 192.168.16.1 0 0 65332 i
R6#sh ip route
Codes: 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
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
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
B 192.168.15.0/24 [20/0] via 192.168.16.1, 00:39:10
172.11.0.0/32 is subnetted, 2 subnets
B 172.11.11.1 [20/0] via 192.168.16.1, 00:39:10
B 172.11.11.3 [20/0] via 192.168.16.1, 00:39:10
172.12.0.0/32 is subnetted, 2 subnets
B 172.12.12.4 [20/0] via 192.168.16.1, 00:39:10
B 172.12.12.1 [20/0] via 192.168.16.1, 00:39:10
172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
C 172.16.16.1/32 is directly connected, Loopback11
D 172.16.0.0/16 is a summary, 01:59:06, Null0
10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
B 10.11.1.0/24 [20/0] via 192.168.16.1, 00:39:10
B 10.12.1.0/24 [20/0] via 192.168.16.1, 00:39:10
B 10.11.12.0/24 [20/0] via 192.168.16.1, 00:39:10
B 10.12.22.0/24 [20/0] via 192.168.16.1, 00:39:10
B 10.101.1.0/30 [20/0] via 192.168.16.1, 00:39:10
B 10.100.1.0/30 [20/0] via 192.168.16.1, 00:39:10
B 192.168.17.0/24 [20/0] via 192.168.16.1, 00:39:10
C 192.168.16.0/24 is directly connected, FastEthernet0/0
B 192.168.18.0/24 [20/0] via 192.168.16.1, 00:39:10
-------------------------------------------------------------------------
R5#sh ip bgp
BGP table version is 21, local router ID is 192.168.15.10
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 10.11.1.0/24 192.168.15.1 0 0 65332 i
*> 10.11.12.0/24 192.168.15.1 0 0 65332 i
*> 10.12.1.0/24 192.168.15.1 0 65332 i
*> 10.12.22.0/24 192.168.15.1 0 65332 i
*> 10.100.1.0/30 192.168.15.1 0 0 65332 i
*> 10.101.1.0/30 192.168.15.1 0 65332 i
*> 172.11.11.1/32 192.168.15.1 0 0 65332 i
*> 172.11.11.3/32 192.168.15.1 0 65332 i
*> 172.12.12.1/32 192.168.15.1 0 65332 i
*> 172.12.12.4/32 192.168.15.1 0 65332 i
*> 192.168.15.0 0.0.0.0 0 32768 i
* 192.168.15.1 0 0 65332 i
*> 192.168.16.0 192.168.15.1 0 65332 i
*> 192.168.17.0 192.168.15.1 0 0 65332 i
*> 192.168.18.0 192.168.15.1 0 65332 i
R5#sh ip route
Codes: 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
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
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
C 192.168.15.0/24 is directly connected, FastEthernet0/0
172.11.0.0/32 is subnetted, 2 subnets
B 172.11.11.1 [20/0] via 192.168.15.1, 02:23:02
B 172.11.11.3 [20/0] via 192.168.15.1, 02:21:39
172.12.0.0/32 is subnetted, 2 subnets
B 172.12.12.4 [20/0] via 192.168.15.1, 02:24:12
B 172.12.12.1 [20/0] via 192.168.15.1, 02:22:21
10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
B 10.11.1.0/24 [20/0] via 192.168.15.1, 04:05:40
B 10.12.1.0/24 [20/0] via 192.168.15.1, 04:05:40
B 10.11.12.0/24 [20/0] via 192.168.15.1, 04:05:40
B 10.12.22.0/24 [20/0] via 192.168.15.1, 04:05:40
B 10.101.1.0/30 [20/0] via 192.168.15.1, 04:05:40
B 10.100.1.0/30 [20/0] via 192.168.15.1, 04:05:41
B 192.168.17.0/24 [20/0] via 192.168.15.1, 01:53:17
B 192.168.16.0/24 [20/0] via 192.168.15.1, 01:56:03
B 192.168.18.0/24 [20/0] via 192.168.15.1, 01:56:34
----------------------------------------------------------------
R4#sh ip bgp
BGP table version is 29, local router ID is 172.12.12.4
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
r i10.11.1.0/24 172.11.11.3 0 100 0 i
r>i 172.11.11.1 0 100 0 i
* i10.11.12.0/24 172.11.11.1 0 100 0 i
*> 0.0.0.0 0 32768 i
* i10.12.1.0/24 172.12.12.1 0 100 0 i
*> 0.0.0.0 0 32768 i
r>i10.12.22.0/24 172.11.11.3 0 100 0 i
r i 172.12.12.1 0 100 0 i
r>i10.100.1.0/30 172.11.11.1 0 100 0 i
r i 172.12.12.1 0 100 0 i
* i10.101.1.0/30 172.11.11.3 0 100 0 i
*> 0.0.0.0 0 32768 i
r>i172.11.11.1/32 172.11.11.1 0 100 0 i
r>i172.11.11.3/32 172.11.11.3 0 100 0 i
r>i172.12.12.1/32 172.12.12.1 0 100 0 i
*> 172.12.12.4/32 0.0.0.0 0 32768 i
*>i192.168.15.0 172.11.11.1 0 100 0 i
Network Next Hop Metric LocPrf Weight Path
* 192.168.16.0 192.168.16.10 0 0 65116 i
*> 0.0.0.0 0 32768 i
*>i192.168.17.0 172.11.11.1 0 100 0 i
* 192.168.18.0 192.168.18.10 0 0 65118 i
*> 0.0.0.0 0 32768 i
R4#sh ip route
Codes: 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
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
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
B 192.168.15.0/24 [200/0] via 172.11.11.1, 01:59:50
172.11.0.0/32 is subnetted, 2 subnets
O 172.11.11.1 [110/2] via 10.11.12.1, 04:19:29, FastEthernet2/0
O 172.11.11.3 [110/2] via 10.101.1.1, 04:17:12, FastEthernet0/1
172.12.0.0/32 is subnetted, 2 subnets
C 172.12.12.4 is directly connected, Loopback11
O 172.12.12.1 [110/2] via 10.12.1.1, 04:18:59, FastEthernet0/0
172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
D 172.16.18.1/32
[90/156160] via 192.168.18.10, 02:18:35, FastEthernet1/1
D 172.16.0.0/16 [90/156160] via 192.168.16.10, 02:06:57, FastEthernet1/0
10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
O 10.11.1.0/24 [110/2] via 10.101.1.1, 04:17:12, FastEthernet0/1
[110/2] via 10.11.12.1, 04:19:29, FastEthernet2/0
C 10.12.1.0/24 is directly connected, FastEthernet0/0
C 10.11.12.0/24 is directly connected, FastEthernet2/0
O 10.12.22.0/24 [110/2] via 10.101.1.1, 04:17:13, FastEthernet0/1
[110/2] via 10.12.1.1, 04:18:59, FastEthernet0/0
C 10.101.1.0/30 is directly connected, FastEthernet0/1
O 10.100.1.0/30 [110/2] via 10.12.1.1, 04:18:59, FastEthernet0/0
[110/2] via 10.11.12.1, 04:19:29, FastEthernet2/0
B 192.168.17.0/24 [200/0] via 172.11.11.1, 01:59:47
C 192.168.16.0/24 is directly connected, FastEthernet1/0
C 192.168.18.0/24 is directly connected, FastEthernet1/1-------------------------------------------------------------------
R3#sh ip bgp
BGP table version is 25, local router ID is 172.11.11.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i10.11.1.0/24 172.11.11.1 0 100 0 i
*> 0.0.0.0 0 32768 i
r>i10.11.12.0/24 172.11.11.1 0 100 0 i
r i 172.12.12.4 0 100 0 i
r i10.12.1.0/24 172.12.12.4 0 100 0 i
r>i 172.12.12.1 0 100 0 i
* i10.12.22.0/24 172.12.12.1 0 100 0 i
*> 0.0.0.0 0 32768 i
r>i10.100.1.0/30 172.11.11.1 0 100 0 i
r i 172.12.12.1 0 100 0 i
* i10.101.1.0/30 172.12.12.4 0 100 0 i
*> 0.0.0.0 0 32768 i
r>i172.11.11.1/32 172.11.11.1 0 100 0 i
*> 172.11.11.3/32 0.0.0.0 0 32768 i
r>i172.12.12.1/32 172.12.12.1 0 100 0 i
r>i172.12.12.4/32 172.12.12.4 0 100 0 i
*>i192.168.15.0 172.11.11.1 0 100 0 i
Network Next Hop Metric LocPrf Weight Path
*>i192.168.16.0 172.12.12.4 0 100 0 i
*>i192.168.17.0 172.11.11.1 0 100 0 i
*>i192.168.18.0 172.12.12.4 0 100 0 i
R3#sh ip route
Codes: 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
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
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
B 192.168.15.0/24 [200/0] via 172.11.11.1, 01:57:26
172.11.0.0/32 is subnetted, 2 subnets
O 172.11.11.1 [110/2] via 10.11.1.1, 04:14:51, FastEthernet0/0
C 172.11.11.3 is directly connected, Loopback11
172.12.0.0/32 is subnetted, 2 subnets
O 172.12.12.4 [110/2] via 10.101.1.2, 04:14:51, FastEthernet1/0
O 172.12.12.1 [110/2] via 10.12.22.1, 04:14:51, FastEthernet2/0
10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
C 10.11.1.0/24 is directly connected, FastEthernet0/0
O 10.12.1.0/24 [110/2] via 10.101.1.2, 04:14:51, FastEthernet1/0
[110/2] via 10.12.22.1, 04:14:51, FastEthernet2/0
O 10.11.12.0/24 [110/2] via 10.101.1.2, 04:14:51, FastEthernet1/0
[110/2] via 10.11.1.1, 04:14:51, FastEthernet0/0
C 10.12.22.0/24 is directly connected, FastEthernet2/0
C 10.101.1.0/30 is directly connected, FastEthernet1/0
O 10.100.1.0/30 [110/2] via 10.12.22.1, 04:14:52, FastEthernet2/0
[110/2] via 10.11.1.1, 04:14:52, FastEthernet0/0
B 192.168.17.0/24 [200/0] via 172.11.11.1, 01:57:23
B 192.168.16.0/24 [200/0] via 172.12.12.4, 02:00:10
B 192.168.18.0/24 [200/0] via 172.12.12.4, 02:00:13