[Samba] broken pipe

[Helmut Hullen]

Hallo,

on a school server in the neighbourhood Samba 3.0.22 (only SMB server,  
"security = server") serves many Windows2000/XP clients in their  
classrooms.
The last lesson on a friday ends at 13:35, then the pupils shut down the  
clients and leave the room.

In /var/log/warn follows

--------------------------------------

Sep  7 13:39:37 Arktur smbd[31514]:   read_data: read failure for 4
bytes to client 192.168.0.34. Error = No route to host
Sep  7 13:39:37 Arktur smbd[31514]:   write_data: write failure in
writing to client 192.168.0.34. Error Broken pipe
Sep  7 13:39:37 Arktur smbd[31514]:   Error writing 75 bytes to client.
-1. (Broken pipe)

Sep  7 13:48:06 Arktur smbd[31536]:   read_data: read failure for 4
bytes to client 192.168.0.36. Error = No route to host
Sep  7 13:48:06 Arktur smbd[31536]:   write_data: write failure in
writing to client 192.168.0.36. Error Broken pipe
Sep  7 13:48:06 Arktur smbd[31536]:   Error writing 75 bytes to client.
-1. (Broken pipe)

Sep  7 13:48:36 Arktur smbd[31515]:   read_data: read failure for 4
bytes to client 192.168.0.32. Error = No route to host
Sep  7 13:48:36 Arktur smbd[31515]:   write_data: write failure in
writing to client 192.168.0.32. Error Broken pipe
Sep  7 13:48:36 Arktur smbd[31515]:   Error writing 75 bytes to client.
-1. (Broken pipe)

Sep  7 13:51:23 Arktur smbd[31574]:   read_data: read failure for 4
bytes to client 192.168.0.35. Error = No route to host
Sep  7 13:51:23 Arktur smbd[31574]:   write_data: write failure in
writing to client 192.168.0.35. Error Broken pipe

[...]

Sep  7 13:59:24 Arktur smbd[31781]:   read_data: read failure for 4
bytes to client 192.168.0.26. Error = No route to host
Sep  7 13:59:24 Arktur smbd[31781]:   write_data: write failure in
writing to client 192.168.0.26. Error Broken pipe
Sep  7 13:59:24 Arktur smbd[31781]:   Error writing 75 bytes to client.
-1. (Broken pipe)

Sep  7 14:06:56 Arktur smbd[31784]:   read_data: read failure for 4
bytes to client 192.168.0.31. Error = No route to host
Sep  7 14:06:56 Arktur smbd[31784]:   write_data: write failure in
writing to client 192.168.0.31. Error Broken pipe
Sep  7 14:06:56 Arktur smbd[31784]:   Error writing 75 bytes to client.
-1. (Broken pipe)

-------------------------------------------------

It takes about 30 minutes for these messages.

What is the reason for these messages? Show they real errors, or show  
they only "I cannot see the client - maybe it's shut down"?

Please excuse my gerlish!

Viele Gruesse!
Helmut