Re: Snort 2.9.6.2 inline mode problem

[Y M <snort () outlook com>]

How are you testing/connecting the client (icmp echo request sender), the sensor, and the receiver of the icmp? The 
NICs that Snort is using to receive --> pass/drop --> forward traffic should be inline with no IP addresses. From your 
description, it seems that you are using the same interface to ping the box as well as do the IPS work.
P.S.: Please respond to the list and not only to myself. Its a mutual benefit.
YM

Date: Sun, 24 Aug 2014 14:00:20 +0200
Subject: Re: [Snort-users] Snort 2.9.6.2 inline mode problem
From: demonsdebason () gmail com
To: snort () outlook com

The same behavior when running with 'eth1:eth2'.
Yeah, the interfaces are in promiscuous, silly me.
Any ideas?



On Sun, Aug 24, 2014 at 7:34 AM, Y M <snort () outlook com> wrote:





inline.
Date: Sun, 24 Aug 2014 05:02:13 +0200
From: demonsdebason () gmail com
To: snort-users () lists sourceforge net

Subject: [Snort-users] Snort 2.9.6.2 inline mode problem

Hi all.
I've been working on my Snort IPS for some time now. 
Noticed that 'drop' rules are working half-way, I have set the test rule to drop ICMP coming to the sensor from local 
machine:



drop icmp 192.168.1.2 any -> 192.168.1.1 any (msg: "Test rule"; sid:110011;)

Alerts get logged and can view them via BASE, but when I ping from .2 to .1 I get this:
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.



64 bytes from 192.168.1.1 : icmp_seq=1 ttl=64 time=0.216 ms
> From 192.168.1.1 icmp_seq=1 Destination Port Unreachable


64 bytes from 192.168.1.1 : icmp_seq=2 ttl=64 time=0.269 ms

> From 192.168.1.1 icmp_seq=2 Destination Port Unreachable
64 bytes from 192.168.1.1 : icmp_seq=3 ttl=64 time=0.221 ms



So some of them are getting 'blocked'.


When I shutdown Snort I's all fine:
64 bytes from 192.168.1.1 : icmp_seq=8 ttl=64 time=0.226 ms

64 bytes from 192.168.1.1
 : icmp_seq=9 ttl=64 time=0.201 ms

64 bytes from 192.168.1.1 : icmp_seq=10 ttl=64 time=0.253 ms
64 bytes from 192.168.1.1

 : icmp_seq=11 ttl=64 time=0.204 ms

Here is my info:


   ,,_     -*> Snort! <*-
  o"  )~   Version 2.9.6.2 GRE (Build 77) 
   ''''    By Martin Roesch & The Snort Team: http://www.snort.org/snort/snort-team



           Copyright (C) 2014 Cisco and/or its affiliates. All rights reserved.
           Copyright (C) 1998-2013 Sourcefire, Inc., et al.
           Using libpcap version 1.4.0
           Using PCRE version: 7.8 2008-09-05



           Using ZLIB version: 1.2.3
+++++++++++++++++++++++++++
snort   
 41104  4.6  2.0 1675528 1342832 ?     Ssl  04:48   0:00 /usr/sbin/snort
 -D -i eth1::eth2 -u snort -g snort -c /etc/snort/snort.conf -Q 
--daq-mode inline -k none

+++++++++++++++++++++++++++
# Looks like you have double colons "eth1::eth2", as opposed to one colon "eth1:eth2". Not sure if the double colons 
are causing the partial drops.


snort --daq-list
Available DAQ modules:
pcap(v3): readback live multi unpriv
ipfw(v3): live inline multi unpriv
dump(v2): readback live inline multi unpriv

afpacket(v5): live inline multi unpriv



++++++++++++++++++++++++++
snort.conf:
config policy_mode:inline
config daq: afpacket
config daq_dir: /usr/lib64/daq
config daq_mode: inline

config daq_var: buffer_size_mb=1024


I've tried dropping all the ICMPs in the iptables, results are as expected, but Snort still logs the alerts.
Do you have any idea what is the issue here?

# Does Snort log the requests or replies or both? I would image if the NIC is promiscuous, then it would still see the 
requests. 

-- 
Aut viam inveniam aut faciam
:wq!



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-- 
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:wq!

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