why can i get my roommate's MAC address although i can't ping his computer successfully?

Question

C:\Documents and Settings\computer>arp -a

Interface: 192.168.1.101 --- 0x2
Internet Address Physical Address Type
192.168.1.1 00-xx-xx-xx-3c-xx dynamic


C:\Documents and Settings\computer>ping 192.168.1.100

Pinging 192.168.1.100 with 32 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 192.168.1.100:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\computer>arp -a

Interface: 192.168.1.101 --- 0x2
Internet Address Physical Address Type
192.168.1.1 00-xx-xx-xx-3c-xx dynamic
192.168.1.100 00-xx-85-4e-7c-xx dynamic

C:\Documents and Settings\computer>
ps. i have changed the mac address in order to protect the privacy.
we're in the same LAN.

so why can i get his MAC address?

Answer 1

They probably have windows firewall running (or similar). Not responding to ping's is pretty standard firewall behavior. Walk over to his pc and just get the ip address.

Answer 2

Many of the current firewalls available today will block ping traffic by default...