I've been searching without success to find the answer to what seems an obvious question regarding the use of ip default-network command. To put it into context, consider the scenario..
A core router R1 has the link to the Internet (e1 - 10.1.1.1) via next hop 10.1.1.2
R1 also has a a LAN interface (e0 - 192.168.1.1) and on this segment is a WAN distribution router (192.168.1.2) linking to remote sites.
All routers run EIGRP.
If I configure "ip route 0.0.0.0 0.0.0.0 10.1.1.2" and "redistribute static" on the core router, all routers know about the default route so packets destined for an unknown network find thier way to 10.1.1.2. This is well understood.
Now assume I have not configured the above commands and I want to do the same thing with ip default-network. I am not sure how, e.g.
- If I set "ip default-network 10.0.0.0" on R1, this will distribute a gateway of last resort via EIGRP, but what happens when the packets arrive at R1? There is no default route telling it which HOST to forward to.
- Do I set "ip default-network 10.0.0.0" and "ip route 0.0.0.0 0.0.0.0 10.1.1.2" on R1?
- or something else?
I suppose I am most confused by the way that all the documentation seems to refer to default static route, and ip default-network as somewhat interchangeable, i.e. use one or the other depending on your routing protocol and if/how you want the default route to be advertised, but I cannot get past the fact that ip default-network specifies a NETWORK and ip route 0.0.0.0 0.0.0.0 specifies a HOST. Somewhere I am going to need to tell a router where it's next hop HOST address is for default route, so somewhere I am going to need a static route.
Cheers.
