[LARTC] Why 'ping' only succeed in one direction?

[shen jing <jshen@xxxxxxxxxxxxxx>]

Hi:

I'm using a linux box ( Rh7.1 ) as a router which connect two Solaris2.6

box.
The three computer is interconnected by ethernet, each computer has
only on ethernet adapter.

The following is my network connection :

----------------------------------- ( Ethernet)
|                    ||                   |||
|                    ||                   |||
Sun-1              Linux              Sun-2
210.32.131.97  192.168.1.1(eth0)    192.168.1.8
               210.32.131.166(eth0:0)

Routing table :

   Sun-1:    192.168.1.0/24   ---> 210.32.131.166
                    default -----> 210.32.131.2

   Linux  :    default---> 210.32.131.2
              ( I add no explicit routing  table about the twodirect
               connected network )

  Sun-2 :    default --> 192.168.1.1

While I exec "ping 192.168.1.8 "on Sun-1, it succeed, with 0% packet
loss.

But when I exec  "ping 210.32.131.97" on Sun-2, the ping always hang
with no output, when I interrupt it with "Ctl-C', it shows "100% packet
loss".

I do tcpdump on linux and snoop on Sun to find out what happened, but
all detailed record shows "ICMP echo requect/reply " has been delivered
between Sun-1<-->linux, Linux<-->Sun-2

And I can telnet/ftp between Sun-1 & Sun-2.

Is there someone will do me a favor to explain why this happens ? Is
there any configuration error with my linux box ?

Thanks in advance and each word will be highly appreciated.

James Shen