Re: [BAD] the whole server down with a red-alert-like attack
On Thu, 24 Jan 2002 22:16, Radek Hnilica wrote:
> I made the same experience with some testing script on one of my
> routers. I run that script from cron to often. When the conditions
> were good, the one run end before cron run the next. But once the
[...]
> I resolved my problem with not running that script every minute but
> relax rules and run it vere five or ten munites.
IMHO something that runs every minute should not be in cron, even something
that runs every 5 minutes possibly shouldn't be in cron.
A shell script that does the following should do:
#!/bin/sh
while /bin/true ; do
/usr/local/bin/something
sleep 60
done
So if the script takes hardly any time to run then it runs every minute. If
it takes a lot of resources then it'll run only one copy at a time, and have
a 1 minute break between runs (time for other programs to get some CPU time
etc).
What would be handy would be to have a program that did all this, so I could
do:
/usr/bin/runevery 60seconds /usr/local/bin/something
To get the same result as the above shell script.
Then for even more protection it could have options to monitor and/or limit
CPU usage and log to syslog.
Does this sound good? If I get a dozen people sending me private email
stating that they want to use such a program then I'll write it and add it to
my logtools package.
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