Re: Snort home net and external net question

["Jefferson, Shawn" <Shawn.Jefferson () bcferries com>]

You can do:
 HOME_NET [10.215.0.0/16,![10.215.40.0/24]]

but you then can't do:
EXTERNAL_NET !$HOME_NET

If you set your EXTERNAL_NET to something besides !$HOME_NET it will work of course.  I never did manage to find a way 
around this, and like I mentioned, I had to use multiple configs to treat a range in the middle of my home_net as 
external (which actually worked out much better anyway, since I could have different threshold.conf, rules, etc...)

Maybe there is a way to do it effectively/easily that I wasn't told, or could figure out at the time.

________________________________
From: Andy Berryman [mailto:aberryman () Cymtec com]
Sent: Friday, September 03, 2010 11:50 AM
To: Joel Esler
Cc: snort-users () lists sourceforge net
Subject: Re: [Snort-users] Snort home net and external net question

Now that's just a crazy idea. Why would someone RTFM? Much easier to be lazy and ask.

/sarcasm aside


So, if I'm reading it right, I need to do something like this:

HOME_NET [10.215.0.0/16,![10.215.40.0/24]]
EXTERNAL_NET !$HOME_NET


That would include all of the 10.215.x.x as the home net except 10.215.40.x would be excluded. So then the external net 
!$HOME_NET should work. But it doesn't.

It's too close to holiday weekend for me to be thinking like this, brain usage stopped at 5pm Thursday.


From: Joel Esler [mailto:jesler () sourcefire com]
Sent: Friday, September 03, 2010 12:42 PM
To: Andy Berryman
Cc: snort-users () lists sourceforge net
Subject: Re: [Snort-users] Snort home net and external net question

Check out README.variables in the doc/ directory of the tarball.


On Sep 3, 2010, at 1:01 PM, Andy Berryman wrote:

I tried that, but am getting an error. I'm running 2.8.6.0

Sep  3 16:51:33 (none) snort[18415]: FATAL ERROR: /snort/conf/general.rules(1) Negated IP ranges that are equal to or 
are more general than non-negated ranges are not allowed.  Consider inverting the logic: $EXTERNAL_NET.

var HOME_NET [10.215.0.0/16]
var EXTERNAL_NET [10.215.40.0/24,!$HOME_NET]

Is it b/c my home net is a /16 and the external net I'm trying to add is a /24?


Thanks,
Andy


From: Joel Esler [mailto:jesler () sourcefire com]
Sent: Friday, September 03, 2010 11:53 AM
To: Andy Berryman
Cc: snort-users () lists sourceforge net<mailto:snort-users () lists sourceforge net>
Subject: Re: [Snort-users] Snort home net and external net question

On Sep 3, 2010, at 11:01 AM, Andy Berryman wrote:


If I have my home net of snort set to:

var HOME_NET [10.215.0.0/16]

How can I make my external net be !$HOME_NET and 10.215.40.0/24 subnet?


With recent versions of Snort, you can do positives and negatives in the same variable, but the more specific entry 
needs to come first.

var HOME_NET [10.215.0.0/16]
var EXTERNAL_NET [10.216.40.0/16,!$HOME_NET]

Should work.

Joel

________________________________
This message from Cymtec Systems, Inc. contains confidential information and is solely for the use of the recipient(s) 
named above. If you are not the intended recipient or an agent responsible for delivering it to the intended recipient, 
you are hereby notified that you have received this message in error and that any review, disclosure, copying, 
distribution or use of the contents of this message is strictly prohibited. If you have received this message in error, 
please destroy it immediately and notify Cymtec Systems, Inc. by telephone at +1.314.993.8700 or by return e-mail.
________________________________


________________________________
This message from Cymtec Systems, Inc. contains confidential information and is solely for the use of the recipient(s) 
named above. If you are not the intended recipient or an agent responsible for delivering it to the intended recipient, 
you are hereby notified that you have received this message in error and that any review, disclosure, copying, 
distribution or use of the contents of this message is strictly prohibited. If you have received this message in error, 
please destroy it immediately and notify Cymtec Systems, Inc. by telephone at +1.314.993.8700 or by return e-mail.
________________________________

------------------------------------------------------------------------------
This SF.net Dev2Dev email is sponsored by:

Show off your parallel programming skills.
Enter the Intel(R) Threading Challenge 2010.
http://p.sf.net/sfu/intel-thread-sfd

_______________________________________________
Snort-users mailing list
Snort-users () lists sourceforge net
Go to this URL to change user options or unsubscribe:
https://lists.sourceforge.net/lists/listinfo/snort-users
Snort-users list archive:
http://www.geocrawler.com/redir-sf.php3?list=snort-users