How to configure iBGP with peer group in a Cisco switch? | labeveryday part 50 using GNS3 (2021) 

when to use Ibgp peer group

TASK0::setup basic cisco commands enable conf t ! !change username here ************** ! username ADMINR5 secret cisco ! !change hostname here ************* ! !hostname R5 ip name-server 8.8.8.8 no ip domain-lookup ip domain-name cisco.com enable secret cisco line console 0 login local exec-timeout 0 0 logging synchronous exit line vty 0 4 login local exec-timeout 10 0 transport input ssh exit service password-encryption ip ssh version 2 crypto key generate rsa 812 exit ---------------------------------------------- TASK1::setup interfaces R1:: conf t interface fa 0/0 ip address 192.168.5.1 255.255.255.0 no shut exit interface fa 0/1 ip address 192.168.6.1 255.255.255.0 no shut exit interface serial 0/0 ip address 172.16.5.1 255.255.255.0 no shut exit interface serial 0/1 ip address 172.16.6.1 255.255.255.0 no shut exit interface loopback 0 ip address 1.1.1.1 255.255.255.0 no shut exit end show ip int brief R2:: conf t interface fa 0/0 ip address 192.168.5.2 255.255.255.0 no shut exit interface loopback 0 ip address 2.2.2.1 255.255.255.0 no shut exit end show ip int brief R3:: conf t interface fa 0/1 ip address 192.168.6.2 255.255.255.0 no shut exit interface loopback 0 ip address 3.3.3.1 255.255.255.0 no shut exit end show ip int brief R4:: conf t interface serial 0/0 ip address 172.16.5.2 255.255.255.0 no shut exit interface loopback 0 ip address 4.4.4.1 255.255.255.0 no shut exit interface loopback 56 ip address 56.56.56.56 255.255.255.255 exit interface loopback 65 ip address 65.65.65.65 255.255.255.255 exit end show ip int brief R5:: conf t interface serial 0/1 ip address 172.16.6.2 255.255.255.0 no shut exit interface loopback 0 ip address 5.5.5.1 255.255.255.0 no shut exit end show ip int brief ---------------------------------------- TASK2::add eigrp 56 routing R1:: conf t router eigrp 56 network 192.168.5.0 0.0.0.255 network 192.168.6.0 0.0.0.255 network 172.16.5.0 0.0.0.255 network 172.16.6.0 0.0.0.255 network 1.1.1.0 0.0.0.255 no auto-summary exit R2:: conf t router eigrp 56 network 192.168.5.0 0.0.0.255 network 2.2.2.0 0.0.0.255 no auto-summary exit end show ip route eigrp show ip eigrp neighbor R3:: conf t router eigrp 56 network 192.168.6.0 0.0.0.255 network 3.3.3.0 0.0.0.255 no auto-summary exit end show ip route eigrp show ip eigrp neighbor R4:: conf t router eigrp 56 ! !Don't advertise loopback 56 and 65 ! network 172.16.5.0 0.0.0.255 network 4.4.4.0 0.0.0.255 no auto-summary exit end show ip route eigrp show ip eigrp neighbor R5:: conf t router eigrp 56 network 172.16.6.0 0.0.0.255 network 5.5.5.0 0.0.0.255 no auto-summary exit end show ip route eigrp show ip eigrp neighbor ----------------------------------------- TASK3::add bgp 65005 routing with bgp peer group !Test only !R1:: !conf t !router bgp 65005 !neighbor 4.4.4.1 remote-as 65005 !neighbor 4.4.4.1 update-source loopback 0 !neighbor 2.2.2.1 remote-as 65005 !neighbor 2.2.2.1 update-source loopback 0 !neighbor 3.3.3.1 remote-as 65005 !neighbor 3.3.3.1 update-source loopback 0 !neighbor 5.5.5.1 remote-as 65005 !neighbor 5.5.5.1 update-source loopback 0 ! !create peer group ! !neighbor IBGP !neighbor IBGP peer-group !neighbor IBGP description FOR IBGP !neighbor IBGP update-source loopback 0 !neighbor IBGP remote-as 65005 NOTE: remove BGP and try to advertise neighbor using group R1:: conf t no router bgp 65005 router bgp 65005 neighbor IBGP peer-group neighbor IBGP remote-as 65005 neighbor IBGP description FOR IBGP neighbor IBGP update-source loopback 0 neighbor IBGP allowas-in neighbor IBGP disable-connected-check neighbor IBGP neighbor 2.2.2.1 peer-group IBGP neighbor 3.3.3.1 peer-group IBGP neighbor 4.4.4.1 peer-group IBGP neighbor 5.5.5.1 peer-group IBGP exit end show ip bgp summary R2:: conf t router bgp 65005 neighbor IBGP2 peer-group neighbor IBGP2 description FOR IBGP R2 neighbor IBGP2 remote-as 65005 neighbor IBGP2 update-source loopback 0 neighbor IBGP2 allowas-in neighbor IBGP2 disable-connected-check neighbor 1.1.1.1 peer-group IBGP2 exit end show ip bgp summary R3:: conf t router bgp 65005 neighbor IBGP3 peer-group neighbor IBGP3 description FOR IBGP R3 neighbor IBGP3 remote-as 65005 neighbor IBGP3 update-source loopback 0 neighbor IBGP3 allowas-in neighbor IBGP3 disable-connected-check neighbor 1.1.1.1 peer-group IBGP3 exit end show ip bgp summary R4:: conf t router bgp 65005 neighbor IBGP4 peer-group neighbor IBGP4 description FOR IBGP R4 neighbor IBGP4 remote-as 65005 neighbor IBGP4 update-source loopback 0 neighbor IBGP4 allowas-in neighbor IBGP4 disable-connected-check neighbor 1.1.1.1 peer-group IBGP4 exit end show ip bgp summary R5:: conf t router bgp 65005 neighbor IBGP5 peer-group neighbor IBGP5 description FOR IBGP R5 neighbor IBGP5 remote-as 65005 neighbor IBGP5 update-source loopback 0 neighbor IBGP5 allowas-in neighbor IBGP5 disable-connected-check neighbor 1.1.1.1 peer-group IBGP5 exit end show ip bgp summary debug ip bgp ipv4 unicast 1.1.1.1 updates ! !do a bgp route refresh !R5 should ping loopback 0 of R1 1.1.1.1 NOTE: advertise loopback 56 and 65 from R4 R4:: conf t router bgp 65005 network 56.56.56.56 mask 255.255.255.255 network 65.65.65.65 mask 255.255.255.255 exit end show ip bgp Note: Don't forget to add route-reflector-client @ R1 to fix split horizon and route refresh clear ip bgp * soft --------------------------------- TEST: from R5 ping 56.56.56.56 ping 65.65.65.65