crazy network problem -- sleep?

[stutiredboy]

Adrian Penisoara 写道:
> Hi,
>
> 2009/3/1 stutiredboy <stutiredboy at gmail.com
> <mailto:stutiredboy at gmail.com>>
>
>     hi,all:
>
>     recently , we found a problem that , some server which with FreeBSD
>     6.2 may stop networking after
>     days of services, it is so difficulty express this status, e, such as
>     sleep? i can not ping this server, tracert is also
>     failure, and other services ,network/server seems to be down... but
>     while i insert the keyboard/mouse/crt in ,
>     everything is ok, such as a ring to call the system to wake-up... no
>     errors found in dmesg or /var/log/messages,
>     such as nothing happened...orz，our unlimit args as follow:
>
>     cputime unlimited
>     filesize unlimited
>     datasize 2088152 kbytes
>     stacksize 65536 kbytes
>     coredumpsize unlimited
>     memoryuse unlimited
>     vmemoryuse unlimited
>     descriptors 655000
>     memorylocked unlimited
>     maxproc 5547
>     sbsize unlimited
>
>     plz give me some suggestion to trace the problem or solve it .
>     thanks a
>     lot !
>
>
> First you need to check whether packets are reaching the system and
> whether the response packets are leaving it with tcpdump(8) on the
> appropriate interface.
>
> If you see the packets coming but not coming out then you need to
> check the status of your TCP/IP stack -- e.g. post the output of
> "netstat -m" and "netstat -s". Also check dmesg output for any errors.
>
> If you are using firewall(s) (ipfw/ipfilter/pf) then check the rules
> and the firewall states status; try temporarily disabling the firewall
> (ipfw disable firewall / ipf -D / pfctl -d) and check whether your
> system becomes reachable.
>
> Check CPU load, interrupts, packet stats (systat -vmstat / systat
> -ifstat).
>
> Regards,
> Adrian Penisoara
> EnterpriseBSD
hi, thank you for your help, i can only ssh to the system, so while the
network is down, i can not login in

yes, we have ipfw on , these rules have used a long time, and many other
severs do not have this problem,

this sistutation happened scarce, in different machine rooms, different
isps, different servers, such as hp\dell.

while the network usable, the cpu and system load is normal, i have
checked dmesg and syslog, nothing

special found , where our colleague in machine room insert the keyboard
or mouse in ,then the network

recover , it is so difficult to catch the ouput of tcpdump or other
messages form netstat , the moment you

have the keyboard connected , the network recover... thanks very much !