ASA and EIGRP / Null0 Routes

[GRANT3779]

Hi Folks,

I have seen some unexpected behavior on an ASA with EIGRP but not sure if this is the norm for the EIGRP process on the Firewall (or router in general).

Under the EIGRP Process on a firewall there are no redistribute / route map commands and a blanket network 10.0.0.0.

e.g 

router eigrp 1234

network 10.0.0.0 255.0.0.0

route null0 10.56.6.6 255.255.255.255

This above null0 route is advertised to my neighbors.

There are no interfaces that fall within the Null0 routes.  Only routes to Null0 seem to exhibit this behavior. Is this related to the blanket 10/8 network statement? I would not have thought this would encompass static routes (only interfaces).

[balaji.bandi]

Can you please tell us what is the reason of using ?

network 10.0.0.0 255.0.0.0    <<---do you have really this big network ?

what is your original IP range you used in the network.

10.56.6.6  <-- come under above network range so ?

[GRANT3779]

This was not my doing...I am only working with it now. It was most likely a lazy administrator when this was setup tbh.

There are are multiple 10 /24 networks / interfaces on the firewall, say 5 or 6..ish. I have no interfaces with a /8

Te network statement should still have no part in advertising my static routes though surely? I was under the impression this will "turn eigrp" on the interfaces that fall under the 10 range.

[GRANT3779]

So the Null0 route is seen as a connected interface which in turn means it is advertised by the network statement since it is so wide.

I was not aware the Null0 was treated this way. Just assumed it was treated as a standard static route. Always learning something new!