[Snort-users] HOMENET IP exclusions
jason.r.wallace at ...11827...
Tue Mar 13 08:21:37 EDT 2012
You can't use !$HOME_NET because the lager network space of HOME_NET
[10.0.0.0/8,126.96.36.199/16] becomes the NOT space. You can't say
!10.0.0.0/8 and !10.9.0.0/16.
On Tue, Mar 13, 2012 at 5:02 AM, Nogwai <nogwai at ...15539...> wrote:
> EXTERNAL_NET is set to :
> var EXTERNAL_NET !$HOME_NET
> I've read somewhere that exclusions in the HomeNet are kinda incompatible
> with External_Net. Is it the problem ?
> If yes, and assuming I set my variables like this :
> var HOMENET [10.0.0.0/8,188.8.131.52/16]
> var EXTERNAL_NET !$HOME_NET ![10.9.0.0/16,184.108.40.206/24]
> I'll NOT see alerts coming from excluded IP, right?
> 2012/3/12 Jason Wallace <jason.r.wallace at ...11827...>
>> What is $EXTERNAL_NET set to?
>> On Mon, Mar 12, 2012 at 1:07 PM, Nogwai <nogwai at ...15539...> wrote:
>> > Hi there,
>> > I am trying to exclude some IP/IP range from HOMENET variables. Basicly,
>> > I
>> > don't want to see any alerts coming from some single IP(s) and complete
>> > IP
>> > pools.
>> > So I've configured my HOMENET like this (in snort.ethX.conf) :
>> > var HOMENET [10.0.0.0/8,220.127.116.11/16,![10.9.0.0/16,18.104.22.168/24]]
>> > It appears that I have a lot of traffic coming from interface eth1. So
>> > I've
>> > managed to split the single snort process in three separate process
>> > running
>> > on interfaces eth1:1, eth1:2 and eth1:3 (with different rule-sets on
>> > each).
>> > And replicate the HOMENET variable in each snort.eth1:x.conf.
>> > Looking at snort process, HOMENET variable seems to be not taken from my
>> > snort.eth1:x.conf files but snort.debian.conf (I'm running Alienvault
>> > OpenSource SIEM - OSSIM v3.0, based on Debian 5.0.8 and Snort 22.214.171.124).
>> > So I've modified the DEBIAN_SNORT_HOME_NET to look like this :
>> > DEBIAN_SNORT_HOME_NET="10.0.0.0/8,126.96.36.199/16,![10.9.0.0/16,188.8.131.52/24]"
>> > And then, Snort don't want to restart :
>> > FATAL ERROR: /etc/snort/rules/emerging-dns.rules => Negated IP ranges
>> > that
>> > are equal to or are more-general than non-negated
>> > ranges are not allowed. Consider inverting the logic: $EXTERNAL_NET.
>> > Looking for some hints, I came across this
>> > (http://seclists.org/snort/2010/q3/674), this
>> > (http://seclists.org/snort/2009/q3/267) and read README.variables. But
>> > still
>> > lost. Don't know if the problem is Debian or Snort related...
>> > Actually, I play with CIDR to exclude the above IP inside the
>> > snort.debian.conf file. But this is a bit painful to maintain and I
>> > received
>> > some new exclusions to add to the list every week. I'll appreciate some
>> > light on this :)
>> > Greetings,
>> > Nogwai
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