I am testing a linux box with rh9 with sendmail and DNS. I have configured the network card properly as when I ping the machine it works properly and also when I use DIG command is resolves web addresses properly.

Also I am in a position to send mail out using send mail. My main problem is as follows;

After a while it seems that the network connectivity drops. That is after a couple of hours when I ping it cannot reach the Linux box. Also when I do a tracert it stops at the router.

When the box is working properly I can ping through my windows network. But when the connectivity drops I cannot ping to the linux box. I checked the power to the machine and when I physically go to the machine I can work on the linux box. Then the connectivity is restored.

Please guide me as to why this could be happening.