Snort mailing list archives
Re: CIDR notation question
From: Chris Green <cmg () sourcefire com>
Date: Mon, 14 Jul 2003 08:00:32 -0400
Rich Adamson <radamson () routers com> writes:
A couple of us are having a discuss off list. Does anyone know (for a fact) how snort treats CIDR notation? var HOME_NET [172.16.0.0/23] implies 512 addresses, one broadcast address (172.16.1.255), and 172.16.0.255 is a valid device address. Is there any code that would assume natural subnet masks, or, analyze packets in such a way as to assume 172.16.0.255 is treated differently?
No.
Or, asking the question slightly different... is var HOME_NET [172.16.0.0/24,172.16.1.0/24] treated exactly the same as HOME_NET [172.16.0.0/23] when packets are analyzed?
Functionally the same but there is no optimization phase for the IP addresses that will determine when you could write a subnet more consisely so the latter ends up being more efficient. -- Chris Green <cmg () sourcefire com> Let not the sands of time get in your lunch. ------------------------------------------------------- This SF.Net email sponsored by: Parasoft Error proof Web apps, automate testing & more. Download & eval WebKing and get a free book. www.parasoft.com/bulletproofapps1 _______________________________________________ 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:
- CIDR notation question Rich Adamson (Jul 10)
- Re: CIDR notation question Matt Kettler (Jul 10)
- Re: CIDR notation question Chris Green (Jul 14)