> I had two PM-2eR's lock up similarily one night here a week or so ago. I
> called Livingtson technical support about it. The general feel of the
> problem was a DoS attack that effectively ran the box out of memory.
> Since we could not get into the box we are not positive. Shortly after
> getting the first box back online the second one dropped off line. The
> same symptoms and same solution. On the back of the PM-2eR (in case you
> are not familiar) there is a green "heart-beat" light that blinks every 5
> seconds. When the boxes dropped offline the lights were not blinking.
Heh. Ours was a PM3, which doesn't have a heartbeat, but has a red
ethernet traffic LED, which was still blinking off and on (erratically,
like it still has traffic going through it).
> I tried dialing in, I tried the console port, and telnet, icmp, rlogin
> etc. in every case I got nothing back. It was suggested that I change the
> telnet port on the PM's. I went further then that, I firewalled all TCP
> to and from the PM's at all ingress and egress points to the network.
Will that stop a DoS attack? At risk of getting insults, I was wondering
if any1 can explain what a DoS attack actually is, and what symptoms it
shows and what precautions are possible.
Thanks in advance.
Leonard.