Questions on PT Activity 3.2.2: physical interface or next hub IP address?

workfrom925

I finished this Packet Tracer activity 3.2.2. For traffic from Autonomous System (AS1) to reach ISP and return, the activity asked to configure four static routes to the four subnets in AS1. The activity gives one route example as:

ISP(config)#ip route 192.168.1.4 255.255.255.252 172.16.1.6

With my vague understanding about whether to use IP address or physical interface to direct the traffic, I have this question: Since with the next hub IP address, the ISP have to do a reversive IP look-up to figure out which physical interface to return the traffic, would it be better to use the interface instead of next hub ip:

ISP(config)#ip route 192.168.1.4 255.255.255.252 s0/0/1

I tried this and it works. But I just wonder if this is a better or worse solution.


My second question is, instead of using 4 routes to 4 subnets, I also tried

ISP(config)#ip route 0.0.0.0 0.0.0.0 s0/0/1

The ping from PC1 and PC2 would work too. So is this a easier and better solution then entering 4 routes for 4 subnets?