yes,i'm sorry not to metion them.
the firewall is a cisco product,the PIX version is 6.1<4>
eth0 is the outside port,eth1 is the inside port and eth2 is the dmz port

when it went down i did nothing to it,and it went back to normal i still did nothing but only
restart it twice, and the second time i connected my notepad to it but did nothing

it's really strange and happened before, the suitation was all the same.