en conf t ! hostname R1 no ip domain-lookup line console 0 exec-timeout 0 0 logging synchronous ! int Lo0 ip address 1.1.1.1 255.255.255.255 exit int Lo1 ip address 1.10.0.1 255.255.0.0 exit int Lo2 ip address 1.20.0.1 255.255.0.0 exit int Lo3 ip address 1.30.0.1 255.255.0.0 exit int Lo4 ip address 1.40.0.1 255.255.0.0 exit int gig0/0 ip address 2.1.1.1 255.255.255.0 no shut exit int gig0/1 ip address 3.1.1.1 255.255.0.0 no shut exit ! router bgp 10 neighbor 2.1.1.2 remote-as 20 neighbor 3.1.1.3 remote-as 30 network 1.1.1.1 mask 255.255.255.255 network 1.10.0.0 mask 255.255.0.0 network 1.20.0.0 mask 255.255.0.0 network 1.30.0.0 mask 255.255.0.0 network 1.40.0.0 mask 255.255.0.0 exit ! end wr
en conf t ! hostname R2 no ip domain-lookup line console 0 exec-timeout 0 0 logging synchronous ! int Lo0 ip address 2.2.2.2 255.255.255.255 exit int gig0/0 ip address 4.2.1.2 255.255.255.0 no shut exit int gig0/1 ip address 2.1.1.2 255.255.255.0 no shut exit ! router bgp 20 neighbor 2.1.1.1 remote-as 10 neighbor 4.2.1.4 remote-as 40 network 2.2.2.2 mask 255.255.255.255 exit ! end wr
en conf t ! hostname R3 no ip domain-lookup line console 0 exec-timeout 0 0 logging synchronous ! int Lo0 ip address 3.3.3.3 255.255.255.255 exit int gig0/0 ip address 3.1.1.3 255.255.255.0 no shut exit int gig0/1 ip address 4.3.1.3 255.255.255.0 no shut exit ! router bgp 30 neighbor 3.1.1.1 remote-as 10 neighbor 4.3.1.4 remote-as 40 network 3.3.3.3 mask 255.255.255.255 exit ! end wr
en conf t ! hostname R4 no ip domain-lookup line console 0 exec-timeout 0 0 logging synchronous ! int Lo0 ip address 4.4.4.4 255.255.255.255 exit int gig0/0 ip address 4.3.1.4 255.255.255.0 no shut exit int gig0/1 ip address 4.2.1.4 255.255.255.0 no shut exit ! router bgp 40 neighbor 4.2.1.2 remote-as 20 neighbor 4.3.1.3 remote-as 30 network 4.4.4.4 mask 255.255.255.255 exit ! end wr
ping with source option by advertised network IP.
because established link network not advertised.
R1#ping 4.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds: ..... Success rate is 0 percent (0/5) R1#ping 4.4.4.4 source 1.1.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds: Packet sent with a source address of 1.1.1.1 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/7 ms
R2#ping 3.3.3.3 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds: ..... Success rate is 0 percent (0/5) R2#ping 3.3.3.3 source 2.2.2.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds: Packet sent with a source address of 2.2.2.2 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/7 ms
R3#ping 4.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 3/4/5 ms R3#ping 1.1.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 3/3/4 ms R3#ping 2.2.2.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds: ..... Success rate is 0 percent (0/5) R3#ping 2.2.2.2 source 3.3.3.3 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds: Packet sent with a source address of 3.3.3.3 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 5/5/6 ms
R4#ping 1.1.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds: ..... Success rate is 0 percent (0/5) R4#ping 1.1.1.1 source 4.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds: Packet sent with a source address of 4.4.4.4 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 5/5/6 ms R4#ping 1.10.0.1 source 4.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.10.0.1, timeout is 2 seconds: Packet sent with a source address of 4.4.4.4 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 5/5/7 ms R4#ping 1.20.0.1 source 4.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.20.0.1, timeout is 2 seconds: Packet sent with a source address of 4.4.4.4 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/6 ms R4#ping 1.30.0.1 source 4.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.30.0.1, timeout is 2 seconds: Packet sent with a source address of 4.4.4.4 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/6 ms R4#ping 1.40.0.1 source 4.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.40.0.1, timeout is 2 seconds: Packet sent with a source address of 4.4.4.4 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/6 ms
R1#sh ip bgp BGP table version is 9, local router ID is 1.40.0.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 0.0.0.0 0 32768 i *> 1.10.0.0/16 0.0.0.0 0 32768 i *> 1.20.0.0/16 0.0.0.0 0 32768 i *> 1.30.0.0/16 0.0.0.0 0 32768 i *> 1.40.0.0/16 0.0.0.0 0 32768 i * 2.2.2.2/32 3.1.1.3 0 30 40 20 i *> 2.1.1.2 0 0 20 i *> 3.3.3.3/32 3.1.1.3 0 0 30 i * 4.4.4.4/32 2.1.1.2 0 20 40 i *> 3.1.1.3 0 30 40 i R1#sh ip ro 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 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, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override, p - overrides from PfR Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 9 subnets, 2 masks C 1.1.1.1/32 is directly connected, Loopback0 C 1.10.0.0/16 is directly connected, Loopback1 L 1.10.0.1/32 is directly connected, Loopback1 C 1.20.0.0/16 is directly connected, Loopback2 L 1.20.0.1/32 is directly connected, Loopback2 C 1.30.0.0/16 is directly connected, Loopback3 L 1.30.0.1/32 is directly connected, Loopback3 C 1.40.0.0/16 is directly connected, Loopback4 L 1.40.0.1/32 is directly connected, Loopback4 2.0.0.0/8 is variably subnetted, 3 subnets, 2 masks C 2.1.1.0/24 is directly connected, GigabitEthernet0/0 L 2.1.1.1/32 is directly connected, GigabitEthernet0/0 B 2.2.2.2/32 [20/0] via 2.1.1.2, 00:08:50 3.0.0.0/8 is variably subnetted, 3 subnets, 2 masks C 3.1.0.0/16 is directly connected, GigabitEthernet0/1 L 3.1.1.1/32 is directly connected, GigabitEthernet0/1 B 3.3.3.3/32 [20/0] via 3.1.1.3, 00:08:49 4.0.0.0/32 is subnetted, 1 subnets B 4.4.4.4 [20/0] via 3.1.1.3, 00:08:49
R2#sh ip bgp BGP table version is 9, local router ID is 2.2.2.2 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 2.1.1.1 0 0 10 i *> 1.10.0.0/16 2.1.1.1 0 0 10 i *> 1.20.0.0/16 2.1.1.1 0 0 10 i *> 1.30.0.0/16 2.1.1.1 0 0 10 i *> 1.40.0.0/16 2.1.1.1 0 0 10 i *> 2.2.2.2/32 0.0.0.0 0 32768 i * 3.3.3.3/32 4.2.1.4 0 40 30 i *> 2.1.1.1 0 10 30 i * 4.4.4.4/32 2.1.1.1 0 10 30 40 i *> 4.2.1.4 0 0 40 i R2#sh ip ro 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 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, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override, p - overrides from PfR Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks B 1.1.1.1/32 [20/0] via 2.1.1.1, 00:08:48 B 1.10.0.0/16 [20/0] via 2.1.1.1, 00:08:48 B 1.20.0.0/16 [20/0] via 2.1.1.1, 00:08:48 B 1.30.0.0/16 [20/0] via 2.1.1.1, 00:08:48 B 1.40.0.0/16 [20/0] via 2.1.1.1, 00:08:48 2.0.0.0/8 is variably subnetted, 3 subnets, 2 masks C 2.1.1.0/24 is directly connected, GigabitEthernet0/1 L 2.1.1.2/32 is directly connected, GigabitEthernet0/1 C 2.2.2.2/32 is directly connected, Loopback0 3.0.0.0/32 is subnetted, 1 subnets B 3.3.3.3 [20/0] via 2.1.1.1, 00:08:23 4.0.0.0/8 is variably subnetted, 3 subnets, 2 masks C 4.2.1.0/24 is directly connected, GigabitEthernet0/0 L 4.2.1.2/32 is directly connected, GigabitEthernet0/0 B 4.4.4.4/32 [20/0] via 4.2.1.4, 00:08:47
R3#sh ip bgp BGP table version is 9, local router ID is 3.3.3.3 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path * 1.1.1.1/32 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i * 1.10.0.0/16 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i * 1.20.0.0/16 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i * 1.30.0.0/16 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i * 1.40.0.0/16 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i * 2.2.2.2/32 3.1.1.1 0 10 20 i *> 4.3.1.4 0 40 20 i *> 3.3.3.3/32 0.0.0.0 0 32768 i *> 4.4.4.4/32 4.3.1.4 0 0 40 i R3#sh ip ro 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 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, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override, p - overrides from PfR Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks B 1.1.1.1/32 [20/0] via 3.1.1.1, 00:08:45 B 1.10.0.0/16 [20/0] via 3.1.1.1, 00:08:45 B 1.20.0.0/16 [20/0] via 3.1.1.1, 00:08:45 B 1.30.0.0/16 [20/0] via 3.1.1.1, 00:08:45 B 1.40.0.0/16 [20/0] via 3.1.1.1, 00:08:45 2.0.0.0/32 is subnetted, 1 subnets B 2.2.2.2 [20/0] via 4.3.1.4, 00:08:45 3.0.0.0/8 is variably subnetted, 3 subnets, 2 masks C 3.1.1.0/24 is directly connected, GigabitEthernet0/0 L 3.1.1.3/32 is directly connected, GigabitEthernet0/0 C 3.3.3.3/32 is directly connected, Loopback0 4.0.0.0/8 is variably subnetted, 3 subnets, 2 masks C 4.3.1.0/24 is directly connected, GigabitEthernet0/1 L 4.3.1.3/32 is directly connected, GigabitEthernet0/1 B 4.4.4.4/32 [20/0] via 4.3.1.4, 00:08:45
R4#sh ip bgp BGP table version is 9, local router ID is 4.4.4.4 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path * 1.1.1.1/32 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i * 1.10.0.0/16 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i * 1.20.0.0/16 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i * 1.30.0.0/16 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i * 1.40.0.0/16 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i *> 2.2.2.2/32 4.2.1.2 0 0 20 i * 3.3.3.3/32 4.2.1.2 0 20 10 30 i *> 4.3.1.3 0 0 30 i *> 4.4.4.4/32 0.0.0.0 0 32768 i R4#sh ip ro 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 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, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override, p - overrides from PfR Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks B 1.1.1.1/32 [20/0] via 4.2.1.2, 00:08:44 B 1.10.0.0/16 [20/0] via 4.2.1.2, 00:08:44 B 1.20.0.0/16 [20/0] via 4.2.1.2, 00:08:44 B 1.30.0.0/16 [20/0] via 4.2.1.2, 00:08:44 B 1.40.0.0/16 [20/0] via 4.2.1.2, 00:08:44 2.0.0.0/32 is subnetted, 1 subnets B 2.2.2.2 [20/0] via 4.2.1.2, 00:08:44 3.0.0.0/32 is subnetted, 1 subnets B 3.3.3.3 [20/0] via 4.3.1.3, 00:08:44 4.0.0.0/8 is variably subnetted, 5 subnets, 2 masks C 4.2.1.0/24 is directly connected, GigabitEthernet0/1 L 4.2.1.4/32 is directly connected, GigabitEthernet0/1 C 4.3.1.0/24 is directly connected, GigabitEthernet0/0 L 4.3.1.4/32 is directly connected, GigabitEthernet0/0 C 4.4.4.4/32 is directly connected, Loopback0
conf t ! ip prefix-list PRE-AS permit 1.10.0.0/16 ! route-map R-ASPRE permit 10 match ip address prefix-list PRE-AS set as-path prepend 10 10 10 exit ! route-map R-ASPRE permit 20 exit ! router bgp 10 neighbor 2.1.1.2 route-map R-ASPRE out exit ! end
debug ip bgp updates clear ip bgp * u all
may route-map not works….
R1#sh route-map route-map R-ASPRE, permit, sequence 10 Match clauses: ip address prefix-lists: PRE-AS Set clauses: as-path prepend 10 10 10 Policy routing matches: 0 packets, 0 bytes route-map R-ASPRE, permit, sequence 20 Match clauses: Set clauses: Policy routing matches: 0 packets, 0 bytes R1#sh ip prefix-list ip prefix-list PRE-AS: 1 entries seq 5 permit 1.10.0.0/24 R1#sh ip proto | section bgp Routing Protocol is "bgp 10" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set IGP synchronization is disabled Automatic route summarization is disabled Neighbor(s): Address FiltIn FiltOut DistIn DistOut Weight RouteMap 2.1.1.2 3.1.1.3 3.1.1.3 Maximum path: 1 Routing Information Sources: Gateway Distance Last Update 3.1.1.3 20 00:06:02 2.1.1.2 20 00:06:00 Distance: external 20 internal 200 local 200 R1#sh run | section router bgp 10 router bgp 10 bgp log-neighbor-changes network 1.1.1.1 mask 255.255.255.255 network 1.10.0.0 mask 255.255.0.0 network 1.20.0.0 mask 255.255.0.0 network 1.30.0.0 mask 255.255.0.0 network 1.40.0.0 mask 255.255.0.0 neighbor 2.1.1.2 remote-as 20 neighbor 2.1.1.2 route-map R-ASPRE out neighbor 3.1.1.3 remote-as 30
oh… prefix-list mask wrong… expected 16, but actual 24…
R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#no ip prefi R1(config)#no ip prefix-list PRE-AS ? deny Specify packets to reject description Prefix-list specific description permit Specify packets to forward seq sequence number of an entry <cr> R1(config)#no ip prefix-list PRE-AS R1(config)#ip prefi R1(config)#ip prefix-list PRE-AS 1.10.0.0/16 ^ % Invalid input detected at '^' marker. R1(config)#ip prefix-list PRE-AS 1.10.0.0/16 *Nov 25 06:06:33.553: BGP(0): (base) 2.1.1.2 send UPDATE (format) 3.3.3.3/32, next 2.1.1.1, metric 0, path 30 *Nov 25 06:06:33.554: BGP(0): (base) 2.1.1.2 send UPDATE (format) 1.1.1.1/32, next 2.1.1.1, metric 0, path Local *Nov 25 06:06:33.581: BGP(0): 2.1.1.2 rcv UPDATE w/ attr: nexthop 2.1.1.2, origin i, originator 0.0.0.0, merged path 20 40 30 10, AS_PATH , community , extended community , SSA attribute *Nov 25 06:06:33.583: BGPSSA ssacount is 0 *Nov 25 06:06:33.583: BGP(0): 2.1.1.2 rcv UPDATE about 1.1.1.1/32 -- DENIED due to: AS-PATH contains our own AS; *Nov 25 06:06:33.584: BGP(0): 2.1.1.2 rcv UPDATE about 1.10.0.0/16 -- DENIED due to: AS-PATH contains our own AS; R1(config)#ip prefix-list PRE-AS 1.10.0.0/16 *Nov 25 06:06:33.584: BGP(0): 2.1.1.2 rcv UPDATE about 1.20.0.0/16 -- DENIED due to: AS-PATH contains our own AS; *Nov 25 06:06:33.585: BGP(0): 2.1.1.2 rcv UPDATE about 1.30.0.0/16 -- DENIED due to: AS-PATH contains our own AS; *Nov 25 06:06:33.586: BGP(0): 2.1.1.2 rcv UPDATE about 1.40.0.0/16 -- DENIED due to: AS-PATH contains our own AS; R1(config)#ip prefix-list PRE-AS permit 1.10.0.0/16
R1#sh route-map route-map R-ASPRE, permit, sequence 10 Match clauses: ip address prefix-lists: PRE-AS Set clauses: as-path prepend 10 10 10 Policy routing matches: 0 packets, 0 bytes route-map R-ASPRE, permit, sequence 20 Match clauses: Set clauses: Policy routing matches: 0 packets, 0 bytes R1#sh ip prefix-list ip prefix-list PRE-AS: 1 entries seq 5 permit 1.10.0.0/16 R1#sh ip proto | sect bgp Routing Protocol is "bgp 10" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set IGP synchronization is disabled Automatic route summarization is disabled Neighbor(s): Address FiltIn FiltOut DistIn DistOut Weight RouteMap 2.1.1.2 3.1.1.3 3.1.1.3 Maximum path: 1 Routing Information Sources: Gateway Distance Last Update 3.1.1.3 20 00:11:43 2.1.1.2 20 00:11:41 Distance: external 20 internal 200 local 200
R4#sh ip bgp BGP table version is 9, local router ID is 4.4.4.4 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path * 1.1.1.1/32 4.2.1.2 0 20 10 i *> 4.3.1.3 0 30 10 i *> 1.10.0.0/16 4.3.1.3 0 30 10 i * 1.20.0.0/16 4.2.1.2 0 20 10 i *> 4.3.1.3 0 30 10 i * 1.30.0.0/16 4.2.1.2 0 20 10 i *> 4.3.1.3 0 30 10 i * 1.40.0.0/16 4.2.1.2 0 20 10 i *> 4.3.1.3 0 30 10 i * 2.2.2.2/32 4.3.1.3 0 30 10 20 i *> 4.2.1.2 0 0 20 i *> 3.3.3.3/32 4.3.1.3 0 0 30 i *> 4.4.4.4/32 0.0.0.0 0 32768 i
no changes
R1#clear ip bgp * soft out R1# *Nov 25 06:08:31.080: BGP(0): (base) 3.1.1.3 send UPDATE (format) 4.4.4.4/32, next 3.1.1.1, metric 0, path 20 40 *Nov 25 06:08:31.081: BGP(0): (base) 2.1.1.2 send UPDATE (format) 3.3.3.3/32, next 2.1.1.1, metric 0, path 30 *Nov 25 06:08:31.083: BGP(0): (base) 3.1.1.3 send UPDATE (format) 2.2.2.2/32, next 3.1.1.1, metric 0, path 20 *Nov 25 06:08:31.084: BGP(0): (base) 2.1.1.2 send UPDATE (format) 1.1.1.1/32, next 2.1.1.1, metric 0, path Local *Nov 25 06:08:31.084: BGP(0): (base) 2.1.1.2 send UPDATE (format) 1.10.0.0/16, next 2.1.1.1, metric 0, path Local *Nov 25 06:08:31.085: BGP(0): (base) 3.1.1.3 send UPDATE (format) 1.1.1.1/32, next 3.1.1.1, metric 0, path Local R1#sh ip proto | sect bgp Routing Protocol is "bgp 10" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set IGP synchronization is disabled Automatic route summarization is disabled Neighbor(s): Address FiltIn FiltOut DistIn DistOut Weight RouteMap 2.1.1.2 3.1.1.3 3.1.1.3 Maximum path: 1 Routing Information Sources: Gateway Distance Last Update 3.1.1.3 20 00:12:58 2.1.1.2 20 00:12:57 Distance: external 20 internal 200 local 200
R1#clear ip bgp * R1# *Nov 25 06:10:08.879: %BGP-3-NOTIFICATION_ALL: sent to all sessions 6/4 (Administrative Reset) R1# *Nov 25 06:10:08.904: %BGP-5-ADJCHANGE: neighbor 2.1.1.2 Down User reset *Nov 25 06:10:08.905: %BGP_SESSION-5-ADJCHANGE: neighbor 2.1.1.2 IPv4 Unicast topology base removed from session User reset *Nov 25 06:10:08.909: %BGP-5-ADJCHANGE: neighbor 3.1.1.3 Down User reset *Nov 25 06:10:08.909: %BGP_SESSION-5-ADJCHANGE: neighbor 3.1.1.3 IPv4 Unicast topology base removed from session User reset
All routers hard reset.
clear ip bgp *
R1#sh ip bgp BGP table version is 9, local router ID is 1.40.0.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 0.0.0.0 0 32768 i *> 1.10.0.0/16 0.0.0.0 0 32768 i *> 1.20.0.0/16 0.0.0.0 0 32768 i *> 1.30.0.0/16 0.0.0.0 0 32768 i *> 1.40.0.0/16 0.0.0.0 0 32768 i * 2.2.2.2/32 3.1.1.3 0 30 40 20 i *> 2.1.1.2 0 0 20 i *> 3.3.3.3/32 3.1.1.3 0 0 30 i * 4.4.4.4/32 2.1.1.2 0 20 40 i *> 3.1.1.3 0 30 40 i
R2#sh ip bgp BGP table version is 10, local router ID is 2.2.2.2 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 2.1.1.1 0 0 10 i *> 1.10.0.0/16 4.2.1.4 0 40 30 10 i * 2.1.1.1 0 0 10 10 10 10 i *> 1.20.0.0/16 2.1.1.1 0 0 10 i *> 1.30.0.0/16 2.1.1.1 0 0 10 i *> 1.40.0.0/16 2.1.1.1 0 0 10 i *> 2.2.2.2/32 0.0.0.0 0 32768 i * 3.3.3.3/32 4.2.1.4 0 40 30 i *> 2.1.1.1 0 10 30 i * 4.4.4.4/32 2.1.1.1 0 10 30 40 i *> 4.2.1.4 0 0 40 i
R3#sh ip bgp BGP table version is 9, local router ID is 3.3.3.3 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path * 1.1.1.1/32 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i *> 1.10.0.0/16 3.1.1.1 0 0 10 i * 1.20.0.0/16 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i * 1.30.0.0/16 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i * 1.40.0.0/16 4.3.1.4 0 40 20 10 i *> 3.1.1.1 0 0 10 i * 2.2.2.2/32 3.1.1.1 0 10 20 i *> 4.3.1.4 0 40 20 i *> 3.3.3.3/32 0.0.0.0 0 32768 i *> 4.4.4.4/32 4.3.1.4 0 0 40 i
R4#traceroute 1.10.0.1 source 4.4.4.4 Type escape sequence to abort. Tracing the route to 1.10.0.1 VRF info: (vrf in name/id, vrf out name/id) 1 4.3.1.3 5 msec 4 msec 5 msec 2 3.1.1.1 6 msec 5 msec 6 msec R4#sh ip bgp BGP table version is 10, local router ID is 4.4.4.4 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path * 1.1.1.1/32 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i *> 1.10.0.0/16 4.3.1.3 0 30 10 i * 1.20.0.0/16 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i * 1.30.0.0/16 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i * 1.40.0.0/16 4.3.1.3 0 30 10 i *> 4.2.1.2 0 20 10 i *> 2.2.2.2/32 4.2.1.2 0 0 20 i * 3.3.3.3/32 4.2.1.2 0 20 10 30 i *> 4.3.1.3 0 0 30 i *> 4.4.4.4/32 0.0.0.0 0 32768 i R4#sh ip ro 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 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, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override, p - overrides from PfR Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks B 1.1.1.1/32 [20/0] via 4.2.1.2, 00:02:58 B 1.10.0.0/16 [20/0] via 4.3.1.3, 00:02:57 B 1.20.0.0/16 [20/0] via 4.2.1.2, 00:02:58 B 1.30.0.0/16 [20/0] via 4.2.1.2, 00:02:58 B 1.40.0.0/16 [20/0] via 4.2.1.2, 00:02:58 2.0.0.0/32 is subnetted, 1 subnets B 2.2.2.2 [20/0] via 4.2.1.2, 00:02:58 3.0.0.0/32 is subnetted, 1 subnets B 3.3.3.3 [20/0] via 4.3.1.3, 00:02:57 4.0.0.0/8 is variably subnetted, 5 subnets, 2 masks C 4.2.1.0/24 is directly connected, GigabitEthernet0/1 L 4.2.1.4/32 is directly connected, GigabitEthernet0/1 C 4.3.1.0/24 is directly connected, GigabitEthernet0/0 L 4.3.1.4/32 is directly connected, GigabitEthernet0/0 C 4.4.4.4/32 is directly connected, Loopback0 R4#sh ip ro 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 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, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override, p - overrides from PfR Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks B 1.1.1.1/32 [20/0] via 4.2.1.2, 00:02:58 B 1.10.0.0/16 [20/0] via 4.3.1.3, 00:02:57 B 1.20.0.0/16 [20/0] via 4.2.1.2, 00:02:58 B 1.30.0.0/16 [20/0] via 4.2.1.2, 00:02:58 B 1.40.0.0/16 [20/0] via 4.2.1.2, 00:02:58 2.0.0.0/32 is subnetted, 1 subnets B 2.2.2.2 [20/0] via 4.2.1.2, 00:02:58 3.0.0.0/32 is subnetted, 1 subnets B 3.3.3.3 [20/0] via 4.3.1.3, 00:02:57 4.0.0.0/8 is variably subnetted, 5 subnets, 2 masks C 4.2.1.0/24 is directly connected, GigabitEthernet0/1 L 4.2.1.4/32 is directly connected, GigabitEthernet0/1 C 4.3.1.0/24 is directly connected, GigabitEthernet0/0 L 4.3.1.4/32 is directly connected, GigabitEthernet0/0 C 4.4.4.4/32 is directly connected, Loopback0 R4#ping 1.10.0.1 source 4.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 1.10.0.1, timeout is 2 seconds: Packet sent with a source address of 4.4.4.4 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 5/6/8 ms
let's say erase route-map explicit permit any.
R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#no route-map R-ASPRE ? <0-65535> Sequence to insert to/delete from existing route-map entry deny Route map denies set operations permit Route map permits set operations <cr> R1(config)#no route-map R-ASPRE pe R1(config)#no route-map R-ASPRE permit ? <0-65535> Sequence to insert to/delete from existing route-map entry <cr> R1(config)#no route-map R-ASPRE permit 20 R1(config)#do sh route-map route-map R-ASPRE, permit, sequence 10 Match clauses: ip address prefix-lists: PRE-AS Set clauses: as-path prepend 10 10 10 Policy routing matches: 0 packets, 0 bytes
R1#sh ip bgp BGP table version is 9, local router ID is 1.40.0.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 0.0.0.0 0 32768 i *> 1.10.0.0/16 0.0.0.0 0 32768 i *> 1.20.0.0/16 0.0.0.0 0 32768 i *> 1.30.0.0/16 0.0.0.0 0 32768 i *> 1.40.0.0/16 0.0.0.0 0 32768 i * 2.2.2.2/32 3.1.1.3 0 30 40 20 i *> 2.1.1.2 0 0 20 i * 3.3.3.3/32 2.1.1.2 0 20 40 30 i *> 3.1.1.3 0 0 30 i * 4.4.4.4/32 2.1.1.2 0 20 40 i *> 3.1.1.3 0 30 40 i
R2#sh ip bgp BGP table version is 10, local router ID is 2.2.2.2 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 4.2.1.4 0 40 30 10 i *> 1.10.0.0/16 4.2.1.4 0 40 30 10 i * 2.1.1.1 0 0 10 10 10 10 i *> 1.20.0.0/16 4.2.1.4 0 40 30 10 i *> 1.30.0.0/16 4.2.1.4 0 40 30 10 i *> 1.40.0.0/16 4.2.1.4 0 40 30 10 i *> 2.2.2.2/32 0.0.0.0 0 32768 i *> 3.3.3.3/32 4.2.1.4 0 40 30 i *> 4.4.4.4/32 4.2.1.4 0 0 40 i
R3#sh ip bgp BGP table version is 9, local router ID is 3.3.3.3 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 3.1.1.1 0 0 10 i *> 1.10.0.0/16 3.1.1.1 0 0 10 i *> 1.20.0.0/16 3.1.1.1 0 0 10 i *> 1.30.0.0/16 3.1.1.1 0 0 10 i *> 1.40.0.0/16 3.1.1.1 0 0 10 i * 2.2.2.2/32 3.1.1.1 0 10 20 i *> 4.3.1.4 0 40 20 i *> 3.3.3.3/32 0.0.0.0 0 32768 i *> 4.4.4.4/32 4.3.1.4 0 0 40 i
R4#sh ip bgp BGP table version is 10, local router ID is 4.4.4.4 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete RPKI validation codes: V valid, I invalid, N Not found Network Next Hop Metric LocPrf Weight Path *> 1.1.1.1/32 4.3.1.3 0 30 10 i *> 1.10.0.0/16 4.3.1.3 0 30 10 i *> 1.20.0.0/16 4.3.1.3 0 30 10 i *> 1.30.0.0/16 4.3.1.3 0 30 10 i *> 1.40.0.0/16 4.3.1.3 0 30 10 i *> 2.2.2.2/32 4.2.1.2 0 0 20 i *> 3.3.3.3/32 4.3.1.3 0 0 30 i *> 4.4.4.4/32 0.0.0.0 0 32768 i
following routes via AS 20 removed from BGP table R1-R4 because implicit route-map deny applied.
R1 does not advertise any routes exclude 1.10.0.0/16 to AS 20 peer.
1.20.0.0/16 1.30.0.0/16 1.40.0.0/16
above destination route, all traffics to AS 10, through AS 30.