Router C Router C send routes send the following routes to router B 250.0.0.0/8 100.0.0.0/8 Router B (SRX) Without the conditions applied the SRX would send the following routes to router A 250.0.0.0/8 100.0.0.0/8 After the following configurations applied the SRX would install a default route into its own routeing table based on the presence of 250/8 and will also advertise the a default and 100/8 to router A Router A Router A routes without conditions met 250.0.0.0/8 1.1.1.2 100.0.0.0/8 1.1.1.2 Router A routes with conditions met 0.0.0.0/0 1.1.1.2 100.0.0.0/8 1.1.1.2 Filter on router A to ensure it only accepts the routes define in route-policy RP-WAN-IN bgp 1 peer 1.1.1.2 as-number 2 # address-family ipv4 unicast network 10.180.0.0 255.255.0.0 peer 1.1.1.2 enable peer 1.1.1.2 route-policy RP-WAN-IN import # route-policy RP-WAN-IN permit node 10 if-match ip address prefix-list PL-WAN-IN # ip prefix-list PL-WAN-IN index 10 permit 0.0.0.0 0 ip prefix-list PL-WAN-IN index 20 permit 100.0.0.0 8 #Peer Statement # Router B SRX set protocols bgp local-as 2 set protocols bgp group AtoB type external set protocols bgp group AtoB local-address 1.1.1.2 set protocols bgp group AtoB export CONDITIONAL_ROUTE #this advertises 0.0.0.0/8 1.1.1.2 and 100.0.0.0/8 1.1.1.2 to router A if they are present in the routing table set protocols bgp group AtoB peer-as 1 set protocols bgp group AtoB neighbor 1.1.1.1 set policy-options policy-statement CONDITIONAL_ROUTE term 1 from route-filter 0.0.0.0/0 exact set policy-options policy-statement CONDITIONAL_ROUTE term 1 from route-filter 100.0.0.0/8 exact set policy-options policy-statement CONDITIONAL_ROUTE term 1 then accept set policy-options policy-statement CONDITIONAL_ROUTE then reject set routing-options generate route 0.0.0.0/0 policy GEN_DEFAULT # generates default towards the advertising router if conditions are met. set policy-options policy-statement GEN_DEFAULT term 1 from protocol bgp set policy-options policy-statement GEN_DEFAULT term 1 from route-filter 250.0.0.0/8 exact set policy-options policy-statement GEN_DEFAULT term 1 then accept set policy-options policy-statement GEN_DEFAULT then reject |
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