[root@localhost cfd]# ping 10.1.1.49
PING 10.1.1.49 (10.1.1.49) 56(84) bytes of data.
64 bytes from 203.197.138.175: icmp_seq=1 ttl=62 time=6.40 ms
64 bytes from 203.197.138.175: icmp_seq=2 ttl=62 time=9.00 ms
64 bytes from 203.197.138.175: icmp_seq=3 ttl=62 time=3.93 ms
64 bytes from 203.197.138.175: icmp_seq=4 ttl=62 time=5.93 ms
64 bytes from 203.197.138.175: icmp_seq=5 ttl=62 time=3.86 ms
64 bytes from 203.197.138.175: icmp_seq=6 ttl=62 time=3.75 ms

--- 10.1.1.49 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 5004ms
rtt min/avg/max/mdev = 3.750/5.480/9.002/1.891 ms
[root@localhost cfd]#


I am ping 10.1.1.49 But what is that IP address 203.197.138.175. Where does it come what it means.?
My IP address is 10.255.240.101.

My guess is that you are doing an internal ping (the ip 10.1.1.49 belongs to a computer within your network) but the host answers back to you with its external ip. How is the networked configured? How many external ip numbers do you have assigned? It seems that the host you are pingin is in a different subnet. To find more about the whereabouts of the host try do "traceroute 10.1.1.49". You can also play with the host command to find out more. You should also try to find info about the existing subnets within the local network.