About bgp routing problems

[cola1998]

Description

hello！
I am currently having this problem when using frr bgp.
bgp establishes neighbor relationships with other switches and receives many routes. (Run command [ vtysh -c "show ip bgp route" ] to view the routes.) The routes are also synchronized to the host. You can run the "route -n" command to find the routes.
However, in our service scenario, many received bgp routes are useless, and a large number of useless routes may cause some faults.
Is there such a configuration that prevents the learned bgp routes from being synchronized to the host? That is, the learned bgp route cannot be found by running the route -n command.

Version

8.2.2

How to reproduce

nothing

Expected behavior

have a configuration that prevents the learned bgp routes from being synchronized to the host

Actual behavior

nothing

Additional context

No response

Checklist

• I have searched the open issues for this bug.
• I have not included sensitive information in this report.

[ton31337]

Without the configuration, topology, and logs we can't help you much.

[cola1998]

1. The configuration of gw is as follows：

!
router bgp 65701
 bgp router-id 10.22.243.118
 no bgp ebgp-requires-policy
 bgp bestpath as-path multipath-relax
 no bgp network import-check
 neighbor 10.22.243.117 remote-as 65143
 neighbor 10.22.243.117 bfd
 neighbor 10.22.243.121 remote-as 65143
 neighbor 10.22.243.121 bfd
 !
 address-family ipv4 unicast
  network 10.251.183.211/32
  network 10.251.247.210/32
  neighbor 10.22.243.117 allowas-in origin
  neighbor 10.22.243.117 route-map RT_OUT out
  neighbor 10.22.243.121 allowas-in origin
  neighbor 10.22.243.121 route-map RT_OUT out
 exit-address-family
exit
!
ip prefix-list PREFIX_MASTER seq 5 permit 10.251.183.211/32
ip prefix-list PREFIX_BACKUP seq 5 permit 10.251.247.210/32
!
route-map RT_OUT permit 10
 match ip address prefix-list PREFIX_MASTER
exit
!
route-map RT_OUT permit 20
 match ip address prefix-list PREFIX_BACKUP
 set as-path prepend 65701
exit
!
route-map RT_OUT deny 30
exit
!

2. topology follow as
   
   we establish connection between tor and gw, gw will receive and learn some routes from tor. now we not want to those routes can show in host side .
3. which part of logs you want to see?

[ton31337]

What do you mean host? Where is the host in this diagram?

[cola1998]

Thank you for your answer.
I would like to ask you how to synchronize the learned bgp route to the host side? Maybe there's something I can do to stop this synchronization.

[ton31337]

First, show what you have under show ip bgp, and show ip route.

[cola1998]

Yes, I can view the received bgp routes through this method.
However, considering the large number of routes, I cannot compare the two routing information one by one.