[Snort-users] Newbie question: reject rule for IPv6

K b urbestfriend at ...11827...
Mon Dec 12 04:01:22 EST 2011

After debugging the snort using gdb, I found out the problem.

Apparently I haven't specified -Q option as part of command line
argument and some how "daq-mode: inline" in snort.conf is being
ignored only when proto is set to ipv6.


On Mon, Dec 12, 2011 at 12:24 PM, K b <urbestfriend at ...11827...> wrote:
> Just to add some more info.
> I tried ipq too without any success. But If I run my web server on an
> IPv4 address and run snort in ip4 mode, I see that request gets
> blocked.
> I am wondering whether I have missed some step for Ipv6 or do I need
> to change the rule for IPv6?
> On Sun, Dec 11, 2011 at 4:09 PM, K b <urbestfriend at ...11827...> wrote:
>> JJ,
>> I am using following command to start snort.
>> snort -c  /etc/snort.conf -N -D
>> Also I have set following parameters in snort.conf.
>> config daq: nfq
>> config daq_mode: inline
>> config daq_var: proto=ip6
>> config daq_dir:<dir>
>> Note that I have built both daq and snort with --ipv6-enabled option.
>> My ip6table:
>> -A INPUT -d <ip_address>/128 -p tcp -m tcp --dport 80 -j NFQUEUE --queue-num 0
>> The setup  works fine as I am seeing alerts getting logged when I send
>> a http request with URI contains "snort-test", but unfortunately the
>> request is not getting rejected ( No ICMP6 unreachable ) as it
>> should've been and request is going through.
>> In fact I tried 'drop' too , without any success. Can someone point
>> out the code where ICMP unreachable is sent ? I tried to debug daq and
>> always verdict to NFQUEUE is set as NF_ACCEPT.
>> Thanks for the response.
>> Regards,
>> Kumar
>> On Sat, Dec 10, 2011 at 9:16 PM, JJ Cummings <cummingsj at ...11827...> wrote:
>>> What does your iptables look like and what is your snort startup command line? Also, use drop, not reject.
>>> Sent from the iRoad
>>> On Dec 9, 2011, at 5:48, K b <urbestfriend at ...11827...> wrote:
>>>> Hello,
>>>> A newbie here and I was trying to setup snort inline with NFQ for IPv6
>>>> services.  Just for testing I have added the following reject rule.
>>>> reject tcp any any -> any 80 (classtype:attempted-user;
>>>> msg:"Snort_test"; content:"snort-test"; sid:9000001; rev:1;)
>>>> Now If I send a traffic with the above content, I see that alerts are
>>>> getting generated but this requests is not being reset as expected.
>>>> I am running snort, my snort.conf is unchanged. What am I doing wrong?
>>>> Have a good day.
>>>> Thanks and regards,
>>>> Kumar
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