classless - no ip classless

im baffled at the topic about classless in the icnd2 book which has this diagram that, when he ping an ip 168.13.1.101 which is not included in the routing table, but has a default route to R1 which has a default route to 0.0.0.0

the result was failed but after, typing the command ip classless command, the ping was now successful.

I just thought, why do i need to use ip classless command (except the fact that the IP is really a classless) I just need clarity why trouble to type this command[/b]

Hi pedenski

ip classless is there by default on newer router models. So you don't have to type it in the config except on old routers like the 2500 series.

Another member asked a related question here:

www.firewall.cx/ftopic-6362-previous.html

The answers might help