Hi,
I have a public /24 network split into two /25 networks, and we have two routers with separate ISP connections. (same ISP) The plan now is to load balance the two /25 networks over the two ISP connections, with each connection acting as a failover for the other. I’m working together with my ISP in order to accomplish this, and we’ve had some difficulties getting it working. Originally I advertised both /25 individually on both routers and they tried to work it out on their end, but we couldn’t get it working properly. Finally they suggested to advertise only the primary /25 network on each router, and then the whole /24 network. Herein my problem seems to lie.
Original configuration:
/routing bgp connection
add as=65001 disabled=no instance=bgp-instance-1 local.address=x.x.x.75 .role=ebgp-peer name=bgp1 output.network=BGP_ADVERTISE remote.address=x.x.x.74/32 .as=65000 routing-table=main
/ip firewall address-list
add address=x.x.x.0/25 list=BGP_ADVERTISE
add address=x.x.x.128/25 list=BGP_ADVERTISE
> routing/bgp/advertisements/print
Columns: DST, PEER, AFI, NEXTHOP
DST PEER AFI NEXTHOP
x.x.x.0/25 bgp1-1 ip x.x.x.75
x.x.x.128/25 bgp1-1 ip x.x.x.75
x.x.x.170/31 bgp1-1 ip x.x.x.74
Routes are advertised as they should be. I then adjust the address list to advertise /25 + /24.
/ip firewall address-list
add address=x.x.x.0/24 list=BGP_ADVERTISE
add address=x.x.x.0/25 list=BGP_ADVERTISE
> routing/bgp/advertisements/print
Columns: DST, PEER, AFI, NEXTHOP
DST PEER AFI NEXTHOP
x.x.x.0/25 bgp1-1 ip x.x.x.75
x.x.x.170/31 bgp1-1 ip x.x.x.74
The /24 does not get advertised. Confirmed also by the ISP.
Is this the intended behaviour? Any workarounds?
I’m not super comfortable with BGP, so I can’t say why everything has been done the way it has been done.