Snort mailing list archives
Re: trouble with inline mode
From: James Lay <jlay () slave-tothe-box net>
Date: Wed, 27 Aug 2014 09:05:51 -0600
On 2014-08-27 07:52, Richard Smollett wrote:
IP setup looks like this. root@snort:~# ifconfig eth0 Link encap:Ethernet HWaddr 08:00:27:fd:b5:c4 inet addr:172.28.61.104 Bcast:172.28.61.127 Mask:255.255.255.128 inet6 addr: fe80::a00:27ff:fefd:b5c4/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:472894 errors:5 dropped:15 overruns:0 frame:0 TX packets:15266 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:129789824 (123.7 MiB) TX bytes:2332609 (2.2 MiB) Interrupt:10 Base address:0xd020 eth1 Link encap:Ethernet HWaddr 08:00:27:97:66:ff inet addr:192.168.123.1 Bcast:192.168.123.255 Mask:255.255.255.0 inet6 addr: fe80::a00:27ff:fe97:66ff/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:14 errors:0 dropped:0 overruns:0 frame:0 TX packets:438796 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:962 (962.0 B) TX bytes:123829936 (118.0 MiB) Interrupt:9 Base address:0xd240 The eth0 interface is the outside and eth1 is inside. Im starting snort with this command. snort --daq afpacket -i eth0:eth1 --daq-mode inline -c /etc/snort/snort.conf But I still cannot ping an inside host from the outside. I can ping between the snort device and inside/ouside hosts. If I ping an inside host from the outside, tcpdump shows the icmp echo request arriving but no reply. Inside host ip is 192.168.123.2. Can anyone recommend some other troubleshooting steps or suggest where I may have left anything out of the setup?
Ah....yea that's the issue. With --daq-mode inline snort will create it's own bridge (that you have no control over). This type of deployment works really well as having snort on it's own machine inline such as: (Internet) <-> (SnortIPS) <-> (LinuxRouter) <-> (Switch) I think you and I were in the same boat where we had a linux router that we wanted to put IPS on. You can use the nfq daq functionality like so: snort -Q -D --daq nfq --daq-var device=eth0 --daq-var queue=1 -c /usr/local/etc/snort/snort.conf /sbin/iptables -t nat -I PREROUTING -j NFQUEUE --queue-num 1 or /sbin/iptables -I INPUT -j NFQUEUE --queue-num 1 But I'm going to be honest...I never got nfq to work well. There's a thread on the list that talks heavily about this, but in a nutshell as soon as a packet hits the snort queue, it is either dropped as an IPS hit, or accepted and sent along, which means any iptables rules AFTER the snort queue rule are not referenced, so be warned and make sure to nmap the external IP after you make the changes. It really seems like the IPS functionality is more suited for the IPS on it's own dedicated machine and not integrated into a router. My two cents :) James ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ 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!
Current thread:
- trouble with inline mode Richard Smollett (Aug 27)
- Re: trouble with inline mode VM PC (Aug 27)
- Re: trouble with inline mode James Lay (Aug 27)