On 02/06/2017 03:16 PM, Robert Moskowitz wrote: > My server hung yesterday. I did not notice it; at this stage in the > game, I should be much more aware... > > I looked into /var/log/messages and my last entry was: > > Feb 5 15:03:46 medon kernel: conntrack: generic helper won't handle > protocol 47 > . Please consider loading the specific helper module. > > So I don't know if someone knocked me over with a GRE based attack, if > the drive is bad, if the board is bad, or the OS has a problem. > > So simple things to start with. I see an earlier GRE warning in > messages: > > Feb 5 03:29:49 medon kernel: conntrack: generic helper won't handle > protocol 47. Please consider loading the specific helper module. > > So it is probably not a stack problem with attacking GRE bots. BTW, is > there some 'easy' way to just block these? $IPTABLES -A INPUT -i $EXTERNAL_INTERFACE -p gre -j REJECT