Configure the firewall to receive BGP traffic from the WAN security zone:
esr-R3(config)# object-group service og_bgp
esr-R3(config-object-group-service)# port-range 179
esr-R3(config-object-group-service)# exit
esr-R3(config)# security zone wan
esr-R3(config-zone)# exit
esr-R3(config)# security zone-pair wan self
esr-R3(config-zone-pair)# rule 100
esr-R3(config-zone-pair-rule)# match protocol tcp
esr-R3(config-zone-pair-rule)# match destination-port og_bgp
esr-R3(config-zone-pair-rule)# action permit
esr-R3(config-zone-pair-rule)# enable
esr-R3(config-zone-pair-rule)# exit
esr-R3(config-zone-pair)# exit
Specify that the interfaces belong to the security zone:
esr-R3(config)# interface gigabitethernet 1/0/1
esr-R3(config-if-gi)# security-zone wan
esr-R3(config-if-gi)# exit
esr-R3(config)# interface gigabitethernet 1/0/2
esr-R3(config-if-gi)# security-zone wan
esr-R3(config-if-gi)# exit
Create a route-map, which will be used later when configuring enabling advertising to routers from another AS.
esr-R3(config)# route-map bgp-general
esr-R3(config-route-map)# rule 1
esr-R3(config-route-map-rule)# match ip address 80.66.0.0/24
esr-R3(config-route-map-rule)# match ip address 80.66.16.0/24
esr-R3(config-route-map-rule)# action permit
esr-R3(config-route-map-rule)# exit
esr-R3(config-route-map)# exit
Create BGP process for AS 2500 and enter process parameters' configuration mode:
esr(config)# router bgp 2500
Configure advertising of directly connected subnets:
esr-R3(config-bgp)# address-family ipv4 unicast
esr-R3(config-bgp-af)# redistribute connected
esr-R3(config-bgp-af)# exit
Create a neighborhood with the R2 router via iBGP:
esr-R3(config-bgp)# neighbor 219.0.0.2
esr-R3(config-bgp-neighbor)# remote-as 2500
esr-R3(config-bgp-neighbor)# enable