Obliging... Kuya Ruel, [SIZE=5]no offense intended.[/SIZE] (pasensya na sa highlighting, I just want to INFORM some people who
mistakenly say "no pun intended" instead.

)
That is not the DEFAULT IP Address for *ANY* router. In fact, I have yet to encounter any router nor server that uses that as the default IP address. Most of them use 192.168.1.1. I've seen some that use 192.168.0.1, but not ...2.1.
To make this GENERIC, the router's DHCP will then assign an IP address to your PC that has the same first 3 numbers, and a different 4th number.
e.g., router uses 192.168.1.1 will assign your PC 192.168.1.x, x being dependent on the router's default config. My Linksys router uses 192.168.1.150 as the first DHCP-assigned IP addres. YMMV.