Blocking write and read on X.25 sockets

Hi Group,

I have a strange problem in using the X.25 under linux. I have a
server listenining on x.25 socket and a x.25 client sending data to the server. The client writes data in a chunk of 256 bytes in a while loop and the server stores the data received to a file. Things work fine for sometime. But, after successfully transferring some data (size varies from about 50k to 500k) the write call at the client and the read call at the server both blocks. After certain time, both come out indicating "Network unreachable" (error number 101).

I also observe that the server has received about 20k data less that
what is successfully written by the client!

Can anyone help me in identifying what's going wrong!? Here are the
details on my environmet:

NET4: LAPB for Linux. Version 0.01 for NET4.0

X.25 for Linux. Version 0.2 for Linux 2.1.15
LAPB Ethernet driver version 0.01
Redhat Linux: 2.4.2-2
X.25 server address: 123451234512345
x.25 client address: 123451234512344

Thanks and regards,
:)Prasanna