Snort mailing list archives
Re: Odp: Re: Snort inline with Squid
From: James Lay <jlay () slave-tothe-box net>
Date: Sat, 25 Apr 2015 14:49:55 -0600
On Sat, 2015-04-25 at 14:58 +0200, Robert Lasota wrote:
Dnia Piątek, 24 Kwietnia 2015 17:53 James Lay <jlay () slave-tothe-box net> napisał(a) On 2015-04-24 07:06 AM, Robert Lasota wrote: > Dnia Piątek, 24 Kwietnia 2015 13:58 James Lay > <jlay () slave-tothe-box net> napisał(a) > >> On Fri, 2015-04-24 at 09:33 +0200, Robert Lasota wrote: >> >>> Hi, >>> >>> Well, I have problem with running this both apps together on >>> router. Snort (as IPS) inline gets traffic from iptables (QUEUE >>> option), and Squid transparent also (from PREROUTING), and it >>> turned out there is problem to rinning both in that case. I tried >>> these combinations of iptables: >>> >>> # for Snort >>> >>> $iptables -I FORWARD -p tcp --dport 80 -j QUEUE >>> >>> # for Squid >>> $iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT >>> --to-port 3128 >>> >>> $iptables -I FORWARD -p tcp --dport 80 -j QUEUE >>> $iptables -t nat -A OUTPUT -p tcp --dport 80 -j REDIRECT >>> --to-port 3128 >>> >>> $iptables -I OUTPUT -p tcp --dport 80 -j QUEUE >>> $iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT >>> --to-port 3128 >>> >>> .. and nothing. In all cases or Squid doesn't work or Snort. >>> >>> Does somebody have any idea how to solve this difficult case ? I >>> would be appreciated. >>> >>> Robert >> Two interfaces? One internal net, one external net? >> >> James > > Yes, there are 2 nics, one for internet and one for LAN. > > Robert So my setup is I have transparent proxy that's listening on eth0 (192.168.bleh) that forwards out ppp0 (external IP). This takes internal clients and transparently proxies them. If that's your setup, here's how I would do it. Start snort: sudo snort -Q -D --daq nfq --daq-var device=eth0 --daq-var queue=1 -c snort.conf Snort iptables first: $iptables -t mangle -I FORWARD -i eth0 -p tcp --dport 80 -j NFQUEUE --queue-num 1 $iptables -t mangle -I OUTPUT -i eth0 -p tcp --dport 80 -j NFQUEUE --queue-num 1 Now for Squid $iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 3128 This should get you what you need, however keep in mind that snort will need to be started first, and because you're sending ONLY port 80 to the NFQUEUE, that's all snort will see as that's all that's going to the queue. Lastly, you'll need to modify your rules that you want do drop traffic to reflect drop instead of alert...you'll get an alert in your unified (if you're doing that) or fast file (if you're doing that as well) either way with drop or alert, but drop will actively drop the connection. Check the link below for more info: http://www.iptables.info/en/structure-of-iptables.html#MANGLETABLE < scroll up to get a nifty diagram. Hope that helps. James Hi, I did as you said and don't work. Squid is blocking but Snort not working, I mean instead of display alert page it shows some Squid error page "url cannot be retrivered". My commands was: snort -Q -D --daq nfq --daq-var device=eth1 --daq-var queue=1 -c /opt/etc/snort/snort.conf iptables -t mangle -I FORWARD -i eth1 -p tcp --dport 80 -j NFQUEUE --queue-num 1 iptables -t mangle -I OUTPUT -o eth1 -p tcp --dport 80 -j NFQUEUE --queue-num 1 eth1 - LAN interface What is interesting , in above case no packets got in rules in mangle table.. zero: Chain FORWARD (policy ACCEPT 893 packets, 403K bytes) pkts bytes target prot opt in out source destination 0 0 NFQUEUE tcp -- eth1 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 NFQUEUE num 1 Chain OUTPUT (policy ACCEPT 5009 packets, 3240K bytes) pkts bytes target prot opt in out source destination 0 0 NFQUEUE tcp -- * eth1 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 NFQUEUE num 1 I tried add to mangle rules without interface: iptables -t mangle -I FORWARD -p tcp --dport 80 -j NFQUEUE --queue-num 1 iptables -t mangle -I OUTPUT -p tcp --dport 80 -j NFQUEUE --queue-num 1 and now packets got only to OUTPUT chain: Chain FORWARD (policy ACCEPT 12 packets, 989 bytes) pkts bytes target prot opt in out source destination 0 0 NFQUEUE tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 NFQUEUE num 1 Chain OUTPUT (policy ACCEPT 1855 packets, 645K bytes) pkts bytes target prot opt in out source destination 23 5563 NFQUEUE tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 NFQUEUE num 1 ..but still is an error "url cannot be retrivered" Robert ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ 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://sourceforge.net/mailarchive/forum.php?forum_name=snort-users Please visit http://blog.snort.org to stay current on all the latest Snort news!
Ok....I'll dust off the dev box and run it through some tests...stay tuned. James
------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y
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Current thread:
- Odp: Re: Snort inline with Squid Robert Lasota (Apr 24)
- Re: Snort inline with Squid James Lay (Apr 24)
- <Possible follow-ups>
- Odp: Re: Snort inline with Squid Robert Lasota (Apr 25)
- Re: Odp: Re: Snort inline with Squid James Lay (Apr 25)
- Re: Odp: Re: Snort inline with Squid James Lay (Apr 26)
- Re: Odp: Re: Snort inline with Squid James Lay (Apr 25)