Soft-Reconfiguration-Inbound

This scenario demonstrates how to configure the soft-reconfiguration inbound option for a BGP neighbor. When enabled, the router stores all received routes from the neighbor before applying inbound policies. This allows viewing the original routes received (before filtering) using the received-routes command, and enables soft resets to re-apply policies without tearing down the BGP session.

Test iBGP - Neighbor soft-reconfiguration inbound stores routes before filtering

Description

Test to verify that soft-reconfiguration inbound stores received routes before policy filtering. DUT1 advertises two routes (1.1.1.0/24 and 2.2.2.0/24) to DUT0. DUT0 has a prefix-list configured to deny 1.1.1.0/24 and permit all other routes. With soft-reconfiguration inbound enabled, DUT0 stores the original routes received from the neighbor before applying the import policy. This allows verifying that 1.1.1.0/24 does not appear in the BGP routing table because it was filtered, but it is still visible using the received-routes command because soft-reconfiguration inbound preserved the original advertisement.

Scenario

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 address 10.10.0.100/24
set protocols bgp 20 neighbor peer remote-address 10.10.0.200
set protocols bgp 20 neighbor peer remote-as 20
set protocols bgp 20 neighbor peer route-map import FILTER-IN
set protocols bgp 20 neighbor peer soft-reconfiguration inbound
set protocols ip prefix-list DENY-DUM1 rule 10 action deny
set protocols ip prefix-list DENY-DUM1 rule 10 prefix 1.1.1.0/24
set protocols ip prefix-list DENY-DUM1 rule 20 action permit
set protocols ip prefix-list DENY-DUM1 rule 20 le 32
set protocols ip prefix-list DENY-DUM1 rule 20 prefix 0.0.0.0/0
set protocols route-map FILTER-IN rule 10 action permit
set protocols route-map FILTER-IN rule 10 match ip address prefix-list DENY-DUM1
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Set the following configuration in DUT1 :

set interfaces dummy dum0 address 1.1.1.1/24
set interfaces dummy dum1 address 2.2.2.1/24
set interfaces ethernet eth0 address 10.10.0.200/24
set protocols bgp 20 neighbor peer remote-address 10.10.0.100
set protocols bgp 20 neighbor peer remote-as 20
set protocols bgp 20 redistribute connected
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Attention

Verify iBGP session establishes with soft-reconfiguration inbound enabled.

Step 3: Run command protocols bgp show ip summary at DUT0 and check if output matches the following regular expressions:

10.10.0.200.*Established

Attention

Verify that DUT0 receives route 2.2.2.0/24 (not filtered by prefix-list).

Step 4: Run command protocols bgp show ip at DUT0 and check if output matches the following regular expressions:

2.2.2.0/24

Attention

Verify that both routes are stored in received-routes (soft-reconfiguration inbound).

Step 5: Run command protocols bgp show ip neighbors neighbor peer received-routes at DUT0 and check if output matches the following regular expressions:

1.1.1.0/24 [\s\S]*2.2.2.0/24