Firewall Wizards mailing list archives

Re: ipchains FW, monitoring for scans, & how to react to them


From: Danny Rathjens <dkr () hq mycity com>
Date: Tue, 21 Dec 1999 02:36:14 -0500

"R. DuFresne" wrote:

On Mon, 20 Dec 1999, Danny Rathjens wrote:
I'd also like any comments on my two ways of setting ipchains
rules/portsentry and how to respond to probes of my boxen:

1. On a web server I thought it was a cool idea to have portsentry
running and when it detected a connection to some port like 110,
1, or 31337, it would alert me and drop an ipchains rule in place
that would prevent all further connections to any local port
from the 'attacking' ip.  Then I could have a cron'd script go
through and flush these rules every once in a while.  This way
I would prevent any immediately following exploit/scan attempts
from the same host, and still not have to worry about random
dial-up and/or spoofed ip's belonging to my customers not working
at some future time.
So I am trying to foil attempts from a single IP once I know
they are likely up to no good, but I let the shields down after
a little while to avoid any problems with delivering my web
content to the world.

Bad idea for #1
Thanks for the input.
Could you give me a little more insight as to why you say 
this is bad?  Do you think the concept of reacting to the scans
is bad or the implementation?
-- 
"...you are already too old for fairy tales, and by the time it is
printed and bound you will be older still.  But some day you will
be old enough to start reading fairy tales again." -- C. S. Lewis



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