[Snort-users] Need help about Snort - rate_filter

Jack Chuong jack.chuong at ...17034...
Tue Nov 25 02:40:17 EST 2014

Hi all,
I'm Snort newbie, I read manual and installed snort with Centos 6.4 64 bit successfully, this is my test rule:

alert icmp $EXTERNAL_NET any -> $HTTP_SERVERS any (msg:"ICMP test"; sid:10000001; rev:001;)

It works fine, this is Snort alert log when I ping from my windows client to Centos server

11/24-14:52:44.452832  [**] [1:10000001:1]  <eth1> ICMP test [**] [Priority: 0] {ICMP} ->
11/24-14:52:45.453391  [**] [1:10000001:1]  <eth1> ICMP test [**] [Priority: 0] {ICMP} ->
11/24-14:52:46.455391  [**] [1:10000001:1]  <eth1> ICMP test [**] [Priority: 0] {ICMP} ->
11/24-14:52:47.457442  [**] [1:10000001:1]  <eth1> ICMP test [**] [Priority: 0] {ICMP} ->

Now I want to apply rate_filter for my test rule to drop icmp packets if they exceed limit (over 10 packets/s for example)

alert icmp $EXTERNAL_NET any -> $HTTP_SERVERS any (msg:"ICMP test"; sid:10000001; rev:001;)
rate_filter gen_id 1, sig_id 1000001, track by_src, count 1, seconds 10, new_action sdrop, timeout 30

But it's not work, icmp packets from my windows client are not dropped, my client can ping Centos Server regularly (ping -t). How can I make it work and check if it works correctly ?
Should I place rate_filter option in local.rules or in /etc/snort/snort.conf ? After searching I found a topic says that rate_filter should be placed at the end of Step #5: Configure preprocessors , before Step #6: Configure output plugins.

Thanks in advanced.
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