AS prepending

Update 2:

More info. When I have tested the failover by pulling
the plug on the preferred ISP, I do not see my network
in looking glass. Secondly, the backup provider has
told me the the route is not in the (rib).


In that case your only course of action is to ask why the ISP is filtering
your routes. I doubt anyone on this list we be able to divine why the ISP is
filtering your routes.

Have you verified that you're advertising the routes
to them? In Cisco-speak, does

sh ip bgp nei x.x.x.x adv

return what you're expecting?

Also, assuming that your backup ISP is either directly
connected to (or one transit hop away from) your
primary ISP, 3 prepends is too many for what you want.
Try 1 prepend first.

David Barak
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