Hi
I usually prefer not to use IP tracking to manage redundancy. One reasons is that sometime ISPs configure their routers to not respond to ICMP (or they can change this policy in future without warning you), or firewalls could discard this kind of traffic, in some scenario congestion could prevent tracking to work properly.
If you are receiving the default route from both ISP (if not I suggest to discard any other routes), I suggest you to not use IP tracking at all. If I were you I'll configure iBGP between routers 1 and 2 and HSRP on LAN. When network is working good, R1 is HSRP primary and has two path for the default routes: an eBGP path through ISPA and an iBGP path through Router2 and ISPB. Supposing any other BGP path attribute is equal, BGP will prefer eBGP path (otherwise configure a better local preference on Router1).
If link to ISPA goes down (link failure or WAN card failure on Router1) or ISP's router is not reacheable, BGP looses the default route form ISPA but it still has the default through Router2-ISPB. HSRP does'n switch but traffic is routed by Router1 to Router2 and this one will routes traffic to ISP2.
If R1 fails, HSRP switches routers roles, R2 become primary and traffic is routed through ISPB.
Finally note that:
- On Router2 you could avoid eBGP to ISPB, it's enough a default static route redistributed in BGP;
- if you aren't an autonomous system, public IPs change when you swap between ISPA and ISPB so a proper design is required to guarantee that your service are still reachable form Internet
Bye,
enrico.
PS rate if useful
