Hello!
I had to put a static host route pointing to null0 to eliminate some
troublesome traffic for a particular host on an MSFC2 the other day. When I
cleared the static route, the only route left was for the entire /24 (learnt
via IGP), however the CEF entry for the host would not clear, and continued
to point the adjacency to null0.
I ended up creating another static host route for the host and pointing down
the correct path in the network. Then I cleared this route, and the CEF
adjacency reverted to the correct entry, showing the adjacency for the /24
learnt via my IGP.
My question is, is there a particular concern with routes pointed to null0
when it comes to CEF? Shouldn't my removal of the static host route
automatically force CEF to revert to the next best learnt path since the
only thing left in the route-table was the route for the entire /24? Why
should the next-hop make a difference, whether I pointed the static route at
a null0 interface or a serial interface when it comes to CEF? Why didn't
the removal of the route clear the CEF entry the first time but work the
second time?
Most comments are appreciated...
thanks,
Scott Keoseyan
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I had to put a static host route pointing to null0 to eliminate some
troublesome traffic for a particular host on an MSFC2 the other day. When I
cleared the static route, the only route left was for the entire /24 (learnt
via IGP), however the CEF entry for the host would not clear, and continued
to point the adjacency to null0.
I ended up creating another static host route for the host and pointing down
the correct path in the network. Then I cleared this route, and the CEF
adjacency reverted to the correct entry, showing the adjacency for the /24
learnt via my IGP.
My question is, is there a particular concern with routes pointed to null0
when it comes to CEF? Shouldn't my removal of the static host route
automatically force CEF to revert to the next best learnt path since the
only thing left in the route-table was the route for the entire /24? Why
should the next-hop make a difference, whether I pointed the static route at
a null0 interface or a serial interface when it comes to CEF? Why didn't
the removal of the route clear the CEF entry the first time but work the
second time?
Most comments are appreciated...
thanks,
Scott Keoseyan
+++The information transmitted is intended only for the person or entity to
which it is addressed and may contain confidential and/or privileged
material. Any review, retransmission, dissemination or other use of, or
taking of any action in reliance upon, this information by persons or
entities other than the intended recipient is prohibited. If you received
this in error, please contact the sender and destroy any copies of this
document.+++