The smallest subnet match will always be preferred. I’m pretty sure you can remove the NAT component of your fail over by advertising your entire subnet block over both carriers and then advertising the smaller subnets as preferred
For example advertise over both: x/22 Provider A: y/23, Provider B: z/23 That way all IP’s “y” go over provider A always as long as the route is still up. If the route goes down because the link goes down then the best route for “Y”’s traffic becomes the “x" route which is still advertised over provider B. I recommend BGP peering with your provider if you have your own AS# even if you still want to handle the internal traffic like you are. However if you don’t want to BGP peer then you can probably have your ISP advertise the routes as desired for you but they will have to drop the route if your router becomes unavailable which they may or may not be willing/able to do unless you BGP peer. Regarding your actual question I am not sure what your trying to do exactly. It sounds like you may be trying to route based on the source rather then the destination? If you like you can call me and I’d be happy to offer some free advice. I’m quite comfortable with OSPF & BGP. Sincerely, Joshaven Potter Google Hangouts: j...@g2wireless.co Cell & SMS: 1-517-607-9370 supp...@joshaven.com > On Dec 15, 2015, at 10:38 AM, That One Guy /sarcasm > <thatoneguyst...@gmail.com> wrote: > > right or wrong, we have half our IPs going out one provider and the other > half going out the other, no BGP today > > The whole network is the same area, both edge provider routers are > distributing default route, so traffic just goes to the closest edge > (splitting the IP space geographically is not an option) > We have an EOIP tunnel between the two edge routers sending the traffic where > it needs to go > > We have a final failure where if one provider is down, and that IP space is > unusabe the other router will NAT that traffic out the alternate provider > (interim until BGP) the problem is if for any reason the EOIP tunnel goes > down, the NAT starts even though the other provider is still up (for the most > part, the EOIP should not go down unless a provider is down but... > > > I have had no success in finding out how to distribute policy routes, maybe > because you cant or im looking for the wrong terms. Is there a way to say > x.x.x.x/23 via default route distributed from router X and y.y.y.y/23 via > default route distributed from router Y ? > > Is this a matter of filters and different areas? > > -- > If you only see yourself as part of the team but you don't see your team as > part of yourself you have already failed as part of the team.
