ibook ethernet problem

[Bill Roberts]

Hello,
I have been trying to set up an FTP server (proftpd) on my ibook (origina=
l
300 mhz model).
Proftpd works fine, and I can access my computer for short time after lea=
ving
it.  However, after leaving it alone for more than about an hour it stops=

responding, and when I ping it, the pings return "request timed out"
The machine is not set to go to sleep, nor does it log out of the window
manager.  
I am also sure that it is not the effect of the hosts.deny file (it is em=
pty).

I am suspicious that the ethernet card has gone into some idle or sleep
mode, or just stops responding after a certain amount of time.

I was wondering if anyone else has had a similar sort of problem, or coul=
d
offer some advice.  

I'm using yellowdoglinux version 2.1 with the 2.4.10 kernel included with=

the distribution
here is an exerpt from my dmesg with lines relating to eth0
eth0: GMAC at 00:0a:27:d5:e9:94, driver v1.5k4
eth0: PHY ID: 0x00406212
eth0: Found Broadcom BCM5201 PHY
eth0: Link state change, phy_status: 0x782d
eth0:    Link up ! BCM5201/5221 aux_stat: 0x003c
eth0:    Full Duplex: 0, Speed: 10

Thanks for any advice you could offer
_Bill Roberts