mandrake 10.0

I have internet connection in my university.I have an internet connection problem here.
We have internet connection by an proxy server and by DHCP server.i HAVE A PROBLEM IN IP ADDRESS.

look at the result...

linux:~ # ifconfig eth0 10.255.240.102
linux:~ # ping 10.1.1.50
PING 10.1.1.50 (10.1.1.50) 56(84) bytes of data.

--- 10.1.1.50 ping statistics ---
6 packets transmitted, 0 received, 100% packet loss, time 4998ms

linux:~ # ifconfig eth0 10.255.240.104
linux:~ # ping 10.1.1.50
PING 10.1.1.50 (10.1.1.50) 56(84) bytes of data.
64 bytes from 10.1.1.50: icmp_seq=1 ttl=62 time=4.26 ms
64 bytes from 10.1.1.50: icmp_seq=2 ttl=62 time=4.49 ms
64 bytes from 10.1.1.50: icmp_seq=3 ttl=62 time=4.16 ms

--- 10.1.1.50 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 4.163/4.310/4.499/0.150 ms
linux:~ # ifconfig eth0 10.255.240.103
linux:~ # ping 10.1.1.50
PING 10.1.1.50 (10.1.1.50) 56(84) bytes of data.
64 bytes from 10.1.1.50: icmp_seq=1 ttl=62 time=10.1 ms
64 bytes from 10.1.1.50: icmp_seq=2 ttl=62 time=4.27 ms
64 bytes from 10.1.1.50: icmp_seq=3 ttl=62 time=4.18 ms

--- 10.1.1.50 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2001ms
rtt min/avg/max/mdev = 4.185/6.206/10.158/2.795 ms
linux:~ #


here 10.1.1.50 is my proxy server.When i set 10.255.240.102 i can not get the internet connection.For other values of IP address i can get it right..

So that can u please help me to figure out what are the IP address range for which i get the internet connection.

Thanks.

Are there any devices between your host and proxy-server 10.1.1.50 ?
Show output of the "ifconfig" command issued on proxy-server.

[root@localhost root]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:11:09:74:CC0
inet addr:10.255.240.109 Bcast:10.255.255.255 Mask:255.0.0.0
inet6 addr: fe80::211:9ff:fe74:ccd0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:186830 errors:327 dropped:0 overruns:0 frame:0
TX packets:96837 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:40488402 (38.6 Mb) TX bytes:49406630 (47.1 Mb)
Interrupt:23 Base address:0x7000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:207078 errors:0 dropped:0 overruns:0 frame:0
TX packets:207078 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:54249537 (51.7 Mb) TX bytes:54249537 (51.7 Mb)

[root@localhost root]#

No, no, no (o:
Show "ifconfig" and "route" commands output on prtoxy-server! On host 10.1.1.50. Anyway, if you have connectivity from one host to another with one IP address and have not with other IP address it is OSI Layer 3 problem. Take a look on routing, firewalls and ACLs.

Might be an IP conflict.

ooh ...IP conflict i will look it.