Why are remote networks shown differently in route table?

workfrom925

I'm doing Cisco NetAcademy Packet Tracer activity. My question doesn't have anything to do with the activity, but why are the static routes for two similar remote networks, 192.168.4.0 and 192.168.6.0 are shown differently?

S 192.168.4.0/24 is directly connected, FastEthernet0/1
S 192.168.5.0/24 is directly connected, FastEthernet0/1
S 192.168.6.0/24 [1/0] via 192.168.2.2
S 192.168.7.0/24 [1/0] via 192.168.2.2

Screen snapshot: http://i48.tinypic.com/sol7xx.jpg

Fyn

Because the static route to 192.168.4.0 is set with exit interface and 192.168.7.0 with next hop ip address.

theodoxa

There are two ways to do a static route:

1) ip route 10.0.0.1 255.255.255.252 s0/0/0
2) ip route 10.0.0.1 255.255.255.252 10.0.0.2

If you use #1, the route will be labelled "directly connected." If you use #2, it will say "via" the next-hop address you specified.

workfrom925

theodoxa wrote: »

There are two ways to do a static route:

1) ip route 10.0.0.1 255.255.255.252 s0/0/0
2) ip route 10.0.0.1 255.255.255.252 10.0.0.2

If you use #1, the route will be labelled "directly connected." If you use #2, it will say "via" the next-hop address you specified.

Does that seem incorrect to you? Because from the network diagram that I posted, the said networks are not directly connected. Maybe Cisco should update this；=）

networker050184

No it does not seem incorrect. You have to think of the way next hops are resolved for forwarding packets. That is what influences whow these are put into the routing table.

Benson_Harlee

i understand what workfrom means, if you use the outgoing interface in the syntax for a remote network the show ip route command will display it as directly connected which could be confusing. I didn't pick up on this until reading this thread.

networker050184

It shows directly connected because of they way the next hop is resolved. When you use an exit interface the router is going to arp for that address out of the interface. You are basically telling the router that it is directly connected to that interface. Fortunately we have things like proxy arp to save us in situations where it is set like this incorrectly. You can also end up with arp exhaustion as well though.

Everything has its place.

Benson_Harlee

networker050184 i understand what your saying . i just dont understand the circumstaces for using the outgoing interface command. I always thought you could use one command or the other until now. Is proxy arp covered in the ccna?

QHalo

Take a look at this explanation.

Static Routes to an Interface, Not A Next-Hop | Keeping It Classless

Benson_Harlee

Thanks for the link.

networker050184

You see the two extra arp entries on that link. Now imagine if its a default route towards the internet. You are going to be sending arp requests for anything reachable on the internet. The arp table can explode!

Benson_Harlee

I get it now instead of just arping for the next hop address for the 0.0.0.0 network which would get stored in the arp cache it would have arp for each individual route route that the router didnt have a route for.