Hey Rene,
I wanted to ask about using access-lists to solve that classic problem of filtering odd or even routes. Suppose you were asked to create a filter that would allow a route if it were odd in the 2nd octet, and even in the 3rd octet. Obviously, you can accomplish it with this:
ip access-list standard ACL_ALLOWODDEVEN
deny 0.0.0.0 255.254.255.255
deny 0.0.1.0 255.255.254.255
permit any
But what isn’t obvious to me, is why the following does NOT work:
ip access-list standard ACL_COMBO
deny 0.0.1.0 255.254.254.255
permit any
I thought they accomplished the same thing, but doing this in the lab proves me wrong.
Any thoughts?