Ping Request not found (BGP)

[HBSDLJZ]

When A pings B, and C establishes a BGP relationship with D, A can successfully ping B when BGP is turned off. However, when BGP is enabled, C redirects the traffic from D's ens256 network card to the local system and then sends it back to the ens256 network card. The ens256 network card can capture two Ping Request requests, but it cannot capture the Ping Request requests after the replies on ens224 or other network interfaces. How can this problem be resolved?

!
! Zebra configuration saved from vty
!   2023/10/20 09:23:04
!
frr version 9.1-dev-MyOwnFRRVersion
frr defaults traditional
!
hostname localhost.localdomain
!
!
!
router bgp 65534
 bgp router-id 10.10.251.159
 no bgp ebgp-requires-policy
 neighbor 10.10.251.151 remote-as 65535
 neighbor 10.10.251.151 ebgp-multihop
 neighbor 10.10.251.151 update-source 10.10.251.159
 !
 address-family ipv4 unicast
  neighbor 10.10.251.151 allowas-in
 exit-address-family
!
exit
!
!
!
!
!
`

`
!
! Zebra configuration saved from vty
!   2023/10/20 09:23:04
!
frr version 9.1-dev-MyOwnFRRVersion
frr defaults traditional
!
hostname localhost.localdomain
!
!
!
!
interface ens256
 pbr-policy HUIZHU
exit
!
!
nexthop-group TARGET
 nexthop 10.10.249.101
exit
!
!
!
pbr-map HUIZHU seq 100
 match src-ip 10.10.251.0/24
 match dst-ip 10.10.250.0/24
 set nexthop-group TARGET
exit
!
!
!

[HBSDLJZ]

[ton31337]

Router C can't forward the traffic back via the same interface it receives the traffic, or I don't understand your case here?

[HBSDLJZ]

Router C can't forward the traffic back via the same interface it receives the traffic, or I don't understand your case here?

C node uses the BGP protocol to route traffic from the ens256 network interface to the local network and forwards it to D's ens256 network interface. The ens256 network interface on D captures the request twice, indicating that C node successfully forwarded it. However, the forwarded traffic cannot be found on D's ens224 network interface or any other network interface. How can this issue be resolved? The traffic seems to have disappeared. Thank you.

[ton31337]

But C has only one interface, right?

[HBSDLJZ]

yes, but C route is not frr.

[ton31337]

But it has a single interface?

[HBSDLJZ]

yes

…

---- Replied Message ---- | From | Donatas ***@***.***> | | Date | 10/26/2023 18:45 | | To | ***@***.***> | | Cc | ***@***.***>***@***.***> | | Subject | Re: [FRRouting/frr] Ping Request not found (BGP) (Discussion #14643) | But it has a single interface? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread.Message ID: ***@***.***>

[ton31337]

It's not possible to route the traffic in the machines via the same interface, unless it's VLAN/sub-interface.

[HBSDLJZ]

But the ENS256 network card of FRR router D can receive traffic.

[ton31337]

What is the configuration of router C?

[HBSDLJZ]

C is not an FRR router; C is a traffic scrubbing device that supports both inbound and outbound traffic using a single network card. The network interface of C can successfully establish a BGP neighbor relationship with D's ens256.