Hi Rene and everyone,
Recently, We have eBGP configured with our new ISP and everything is working fine. We’re given these subnets 11.12.13.0/30 and 21.22.23.0/24 from our ISP. We also own this public subnet 32.33.34.0/23 and use them as our LAN. My question is, how do we advertise our subnet 32.33.34.0/23 to our eBGP which between our edge router and ISP router? What do we need to modify from our topology?
Hello Andy,
If you want to advertise something in BGP, you need to have that route in your routing table. On your router, you can configure a static route that points to your ASA and then redistribute that static route in BGP. Something like this:
ip route 32.33.34.0 255.255.254.0 21.22.23.1
router bgp 22222
redistribute static
Or, if you want to make sure you only redistribute this static route then you can include a route-map:
ip prefix-list LAN permit 32.33.34.0/23
route-map TO_ISP permit 10
match ip address prefix-list LAN
router bgp 22222
redistribute static route-map TO_ISP
Rene