Snort mailing list archives
Re: Network placement / using a VLAN
From: Erek Adams <erek () snort org>
Date: Tue, 8 Apr 2003 09:43:18 -0500 (EST)
On Mon, 7 Apr 2003, Brian McIntyre wrote:
Local traffic on a single subnet is going into a single switch that allows port mirroring into a port. I have hosts on 10/100 with a single 1000 port that I've added only a couple of mirrored interfaces to. A speedy Snort sensor is in place with a gig card to listen to the traffic and forward alerts to an ACID/MySQL console. I'm happy to say that Snort is working as expected.
Good. :)
Question 1) Since my two mirrored ports are my WAN interface, and my trusted interface on my firewall, is it really necessary to consider adding additional hosts to the mirrored port? If all I'm really concerned about monitoring is incoming and outgoing traffic through those two gateway interfaces isn't that sufficient?
I'm not sure if I'm following what you mean here, so please correct me if I'm wrong. You have two uplink (WAN) interfaces that are mirrored to port X. You are asking should you add LAN host ports to the mirror to sniff the traffic going to/from those hosts. If you're not worried about what's 'inside' of your network, then there's no need to.
Question 2) I would also like to monitor my DMZ. How secure would it be to add a VLAN on my switch to connect my DMZ hosts on the same switch as my local subnet? While physically they reside on the same switch, they will be on seperate VLANs. Can I be certain I'm not introducing a *serious* security risk to my internal network? This might be a much better question to ask my switch vendor, and please shot me if I've lost my marbles..
You could do it, but it's not a perfect solution. You can 'hop' from one VLAN to another with a specially crafted packet [0]. If you're _really_ worried about segregation of traffic, then I'd suggest using two separate pieces of hardware. Cheers! ----- Erek Adams "When things get weird, the weird turn pro." H.S. Thompson [0] http://www.cisco.com/en/US/about/ac123/ac114/ac173/ac222/about_cisco_packet_feature09186a0080142deb.html (URL may wrap) ------------------------------------------------------- This SF.net email is sponsored by: ValueWeb: Dedicated Hosting for just $79/mo with 500 GB of bandwidth! No other company gives more support or power for your dedicated server http://click.atdmt.com/AFF/go/sdnxxaff00300020aff/direct/01/ _______________________________________________ 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:
- Network placement / using a VLAN Brian McIntyre (Apr 07)
- Re: Network placement / using a VLAN Erek Adams (Apr 08)
- <Possible follow-ups>
- RE: Network placement / using a VLAN JP Vossen (Apr 07)