BGP with CARP and two ISP

[Smith 0]

Hello,

For an installation with two PFSense (2.4.5p1) setup in HA and two ISP, I have to announce a /22 network with BGP, the PFSense are running with opengbp (not FRR for now).

Here is the schematic :

With a single ISP, this is not a problem to announce the /22 network behind the PFSense, (I used RFC 1918 addresses as example):

In Services -> OpenBGPD -> Settings ->
network 192.168.1.0/22 set nexthop carp_ip_address

In Services -> OpenBGPD -> Neighbors -> Add the parameter 'set nexthop no-modify'

With this setting I have one feed to each ISP and I don’t have to wait for BGP rebuild in case of failure of one PFSense.

But what about two ISP and CARP, I suppose I can’t announce the same network twice ?

network 192.168.1.0/22 set nexthop carp_isp1
network 192.168.1.0/22 set nexthop carp_isp2

In this thread :

https://forum.netgate.com/topic/51849/openbgp-with-carp-nexthop-carp-ip-carp

a solution is provided but I can’t get through the logic and how network is announced.

Can someone help me for this ?

Thanks !

[Smith 0]

@smith-0 said in BGP with CARP and two ISP:

With this setting I have one feed to each ISP and I don’t have to wait for BGP rebuild in case of failure of one PFSense.

Should read :
With this setting I have two feeds from both PFSense to the ISP and I don’t have to wait for BGP rebuild in case of failure of one PFSense.