Snort mailing list archives
RE: Passing IP Addresses best practices
From: "Mike Burkhouse" <mburkhouse () learningvoyage com>
Date: Tue, 23 Sep 2003 13:44:36 -0400
This was incredibly informative. Thanks again, Erik. I appreciate you help. Mike -----Original Message----- From: Erek Adams [mailto:erek () snort org] Sent: Tuesday, September 23, 2003 12:39 PM To: Mike Burkhouse Cc: Pig-A-Holics Anonymous Subject: RE: [Snort-users] Passing IP Addresses best practices On Tue, 23 Sep 2003, Mike Burkhouse wrote:
I saw that in the FAQ, but the examples used private IPs. Being fairly new at this, I didn't know if implied that it was a really_bad_idea to pass public IPs, which is why I am asking about best practices. I will definitely look into BPF more closely. Thank you for your advice.
There is a very subtle difference between the two. You need to make sure that you make the right choice for you setup. Basically: * Pass rules. Can be setup to ignore a host or set of hosts. You can even ignore on content. In your case an idea might be: var BLACKBERRY_BOXES [123.456.789.010,123.456.789.011] pass tcp $BLACKBERRY_BOXES any -> $MAIL_SERVERS 110 <stuff> You can adjust the BLACKBERRY_BOXES var as you need or use a CIDR subnet mask such as 10.10.10.0/24. You can also change <stuff> to something specific, or you can just end the rule there. IOW, you can ignore all incoming tcp port 110 traffic from the BBservers to your mailservers, or ignore on something specific by using a 'content: <bleh>' statement. * BPF filter. Drops the data before it even _gets_ to Snort. Very useful if you have a lot of traffic that you want to ignore, since there is not a CPU overhead from using the BPF. snort <options> 'not src host 10.10.10.0/24 and dst port 110 and dst host <foo>' Hope that helps! ----- Erek Adams "When things get weird, the weird turn pro." H.S. Thompson ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ 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
Current thread:
- Passing IP Addresses best practices Mike Burkhouse (Sep 23)
- Re: Passing IP Addresses best practices Erek Adams (Sep 23)
- RE: Passing IP Addresses best practices Mike Burkhouse (Sep 23)
- RE: Passing IP Addresses best practices Erek Adams (Sep 23)
- RE: Passing IP Addresses best practices Mike Burkhouse (Sep 23)
- RE: Passing IP Addresses best practices Mike Burkhouse (Sep 23)
- Re: Passing IP Addresses best practices Erek Adams (Sep 23)
- <Possible follow-ups>
- RE: Passing IP Addresses best practices Richard Brackett (Sep 23)
- Re: Passing IP Addresses best practices jon baer (Sep 23)
- RE: Passing IP Addresses best practices Erek Adams (Sep 24)
- RE: Passing IP Addresses best practices Mervin Pearce (Sep 25)