Route
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... an incomplete access list: some legitimate traffic is filtered for
lack of a route in the filtering router's Forwarding Information
Base ...
... using BGP Communities [2]. That way, the route will always be the
best one in the FIB, even in the scenarios where only the primary
...
... an equivalent, RPF-specific table) but instead of just inserting one
best route there, the alternative paths (if any) have been added as
well, and are valid for consideration. The list is populated using
...
... context in which Feasible RPF
operates. The mechanism relies on consistent route advertisements
(i.e., the same prefix(es), through all the paths) propagating to all
...
... the BGP advertisement to the primary ISP e.g., due to route-maps or
other routing policies not being up-to-date. The failure modes are
...
... to strict RPF, but differs in that it checks only for the existence
of a route (even a default route, if applicable), not where the route
...
... RPF, but differs in that it checks only for the existence
of a route (even a default route, if applicable), not where the route
points to. Practically, this could be considered as a "route ...
... of a route (even a default route, if applicable), not where the route
points to. Practically, this could be considered as a "route
...
... default route, if applicable), not where the route
points to. Practically, this could be considered as a "route
presence check" ("loose RPF is a misnomer in a sense because there is
...
... RPF is found in asymmetric routing
situations: a packet is dropped if there is no route at all, such as
to "Martian addresses ...
... addresses" or addresses that are not currently routed,
but is not dropped if a route exists.
Loose Reverse Path Forwarding ...
... traffic at so-called "Honey Pot" systems or
discarding any traffic they do not have a "real" route to, and
smaller ISPs may well purchase transit capabilities and use a default
route ...
... route to, and
smaller ISPs may well purchase transit capabilities and use a default
route from a larger provider. At least some implementations of Loose
RPF ...
... provider. At least some implementations of Loose
RPF check where the default route points to. If the route points to
the interface ...
... RPF check where the default route points to. If the route points to
the interface where Loose RPF ...
... RPF interface even in the presence of a default route. If such
fine-grained checking is not implemented, presence of a default route
...
... interface even in the presence of a default route. If such
fine-grained checking is not implemented, presence of a default route
nullifies the effect of Loose RPF completely.
...
... RPF
ignoring default routes, i.e., an "explicit route presence check".
In this approach, the router looks up the source address ...
... In this approach, the router looks up the source address in the route
table, and preserves the packet if a route is found. However, in the
lookup ...
... router looks up the source address in the route
table, and preserves the packet if a route is found. However, in the
lookup, default routes ...
... ISPs implement ingress filters (which they should do), the
third option is to route traffic being sourced from a given
provider ...