I moved the question to here from stackoverflow.com

http://stackoverflow.com/questions/2917569/unable-to-ping-server-from-client-b-but-able-to-ping-from-client-a-please-help

I am trying to configure a IIS 6.0/Windows Server 2003 web server with a ASP.net application.

When I try to ping the server from client computer A I get the following:

PING 74.208.192.xxx ==> Ping fails
PING 74.208.192.xxx:80 ==> Ping succeeds!

From client computer B, BOTH the pings fail.

    PING 74.208.192.xxx ==> Ping fails
    PING 74.208.192.xxx:80 ==> Ping fails with a message 
"Ping request could not find host 74.208.192.xxx:80"

Both clients A and B are on the same subnet. The server is outside (a virtual server hosted by an ISP)

I have an ASP.NET application in a virtual directory on the server. In IE or firefox, if I enter http://74.208.192.xxx/subdir/subdir/../Default.aspx, it works from both the clients! The server has default firewall settings but web server enabled (Port 80 is open).

From client A (note the different 'reply to' address when the ping succeeds.

C:\Program Files\Microsoft Visual Studio 9.0\VC>ping 74.208.192.xx

Pinging 74.208.192.xx with 32 bytes of data:

Request timed out.
...
Request timed out.

Ping statistics for 74.208.192.xx:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Program Files\Microsoft Visual Studio 9.0\VC>ping 74.208.192.xx:80

Pinging 74.208.192.xx:80 [208.67.216.xxx] with 32 bytes of data:

Reply from 208.67.216.xxx: bytes=32 time=35ms TTL=54
...
Reply from 208.67.216.xxx: bytes=32 time=33ms TTL=54

Ping statistics for 208.67.216.xxx:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 32ms, Maximum = 54ms, Average = 38ms

From client B

C:\Documents and Settings\user>ping 74.208.192.81

Pinging 74.208.192.81 with 32 bytes of data:

Request timed out.
...
Request timed out.

Ping statistics for 74.208.192.81:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\user>ping 74.208.192.81:80
Ping request could not find host 74.208.192.81:80. Please check the name and try
 again.

My main problem is I have a web service (asmx) file and the web service client program is not able to access it from client B, but able to access it from client A. I am trying to find out why and thought this ping issue may shed some light.

I can ping yahoo.com both the computers.