Snort mailing list archives
Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6
From: Dheeraj Gupta <dheeraj.gupta4 () gmail com>
Date: Fri, 18 Dec 2015 16:39:59 +0530
Hi, I am also confused about the drop count. This is what I got after a separate brief snort run (on a different machine) =============================================================================== Run time for packet processing was 497.799669 seconds Snort processed 7139620 packets. Snort ran for 0 days 0 hours 8 minutes 17 seconds Pkts/min: 892452 Pkts/sec: 14365 =============================================================================== Packet I/O Totals: Received: 14977160 Analyzed: 7139620 ( 47.670%) Dropped: 11666105 ( 43.786%) Filtered: 7046472 ( 47.048%) Outstanding: 791068 ( 5.282%) Injected: 0 =============================================================================== The totals and percentages do not tally. Can someone explain how filtered, received, analyzed and dropped numbers should be interpreted? Regards, Dheeraj On Thu, Dec 17, 2015 at 11:46 AM, Dheeraj Gupta <dheeraj.gupta4 () gmail com> wrote:
Hi, The test was run for the same PCAP so number of packets is same in both cases (9220233). The packet I/O totals as output by two snorts are: Snort-2.9.8.0 ------------------------ =============================================================================== Run time for packet processing was 783.512468 seconds Snort processed 9220233 packets. Snort ran for 0 days 0 hours 13 minutes 3 seconds Pkts/min: 709248 Pkts/sec: 11775 =============================================================================== =============================================================================== Packet I/O Totals: Received: 9220233 Analyzed: 9220233 (100.000%) Dropped: 0 ( 0.000%) Filtered: 0 ( 0.000%) Outstanding: 0 ( 0.000%) Injected: 0 =============================================================================== Snort-2.9.7.6 ----------------------- =============================================================================== Run time for packet processing was 547.131014 seconds Snort processed 9220233 packets. Snort ran for 0 days 0 hours 9 minutes 7 seconds Pkts/min: 1024470 Pkts/sec: 16856 =============================================================================== =============================================================================== Packet I/O Totals: Received: 9220233 Analyzed: 9220233 (100.000%) Dropped: 0 ( 0.000%) Filtered: 0 ( 0.000%) Outstanding: 0 ( 0.000%) Injected: 0 =============================================================================== Again as the test is against a static PCAP, there will be no drops. However, in this test Snort-2.9.8.0 is almost 30% slower (processes about 11.7K pkts/s as against 16.8K pkts/s) than Snort-2.9.7.6. When used with live traffic, wouldn't this cause increased packet drops? Regards, Dheeraj On Wed, Dec 16, 2015 at 8:02 PM, Nageswara Rao A.V.K (navk) < navk () cisco com> wrote:You did not provide “Packet I/O Totals:” for this test. We have to compare that data. I don’t think previous stats will applicable here. Because the number of pkts are different here. Best Regards, -ANR *From:* Dheeraj Gupta [mailto:dheeraj.gupta4 () gmail com] *Sent:* Wednesday, December 16, 2015 5:16 PM *To:* Nageswara Rao A.V.K (navk) *Cc:* snort-devel () lists sourceforge net *Subject:* Re: [Snort-devel] Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Hi, I captured a large PCAP (6.6G ~9M packets) and analyzed it through both Snort-2.9.7.6 and 2.9.8.0 with almost identical configuration file (memcap etc.). Since SO rules for Snort-2.9.7.6 cannot be used with 2.9.8.0, so number of rules for 2.9.8.0 was less (about 11k) as compared to 2.9.7.6 (12k). Here is a summary of end of run stats Snort-2.9.7.6 =============================================================================== Run time for packet processing was 547.131014 seconds Snort processed 9220233 packets. Snort ran for 0 days 0 hours 9 minutes 7 seconds Pkts/min: 1024470 Pkts/sec: 16856 =============================================================================== Snort-2.9.8.0 =============================================================================== Run time for packet processing was 783.512468 seconds Snort processed 9220233 packets. Snort ran for 0 days 0 hours 13 minutes 3 seconds Pkts/min: 709248 Pkts/sec: 11775 =============================================================================== snort.conf is attached On Tue, Dec 15, 2015 at 10:03 AM, Dheeraj Gupta <dheeraj.gupta4 () gmail com> wrote: Hi, The traffic is captured from a live interface, so it is not exactly same. However, it is from the same network and same network filter over a contiguous time range. So, characteristics of the trafic are broadly the same i.e. most of it is user browsing data. The reason I wrote this e-mail is because on a weekday, we have an average 100-150 Mbps on the wire and Snort-2.9.7.6 reported less losses (<10%). However, Snort-2.9.8.0 reported over 40% drops with comparable traffic load/pattern. Snort logs do not have any additional entry apart from session pruned due to timeout/stale (same in both cases). Regards, Dheeraj On Tue, Dec 15, 2015 at 8:43 AM, Nageswara Rao A.V.K (navk) < navk () cisco com> wrote: Hi Dheeraj, We need more info to get in to conclusion. Are you passing same traffic in both scenario’s?? Did you verify snort logs ?? You may know the reason for pkt drops. We did not notice this problems in our observation. More details may help us to analyze the problem. Best Regards, -ANR *From:* Dheeraj Gupta [mailto:dheeraj.gupta4 () gmail com] *Sent:* Monday, December 14, 2015 11:30 AM *To:* snort-devel () lists sourceforge net *Subject:* [Snort-devel] Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Hi, I just upgraded to Snort-2.9.8.0 from Snort-2.9.7.6. Before the upgrade one of my sensors showed (somewhat expected) packet drops. However, after the upgrade the packet drop increased significantly even though the number of rules decreased (as SO rules are not in use with 2.9.8.0). I am still using Snort-2.9.7.6 rulesets (as advised by you). Here is a snip from my snort.stats file for 2.9.8.0 #time,pkt_drop_percent,wire_mbits_per_sec.realtime 1450068900,33.873,124.415 1450069200,23.718,121.253 1450069500,26.014,120.349 1450069800,26.368,120.821 1450070100,23.706,116.493 1450070400,21.039,121.363 For Snort-2.9.7.6, the snip is #time,pkt_drop_percent,wire_mbits_per_sec.realtime 1450071180,0.000,79.159 1450071480,0.000,118.671 1450071780,2.146,132.186 1450072080,8.337,130.408 Looking at end-of-snort stats. This is for 2.9.8.0 Packet I/O Totals: Received: 804563792 Analyzed: 388361098 ( 48.270%) Dropped: 298207658 ( 27.042%) Filtered: 415840607 ( 51.685%) Outstanding: 362087 ( 0.045%) Injected: 0 And this is for 2.9.7.6 Packet I/O Totals: Received: 60969886 Analyzed: 30035104 ( 49.262%) Dropped: 742645 ( 1.203%) Filtered: 30927585 ( 50.726%) Outstanding: 7197 ( 0.012%) Injected: 0 I have a longish BPF filter, so is the filtered count an indication of the amount of traffic which was filtered by that filter? Also is dropped count a subset of analyzed count or received count? I ask this because it appears received_count = analyzed + filtered so dropped_count doesn't really fit in Regards, Dheeraj
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Current thread:
- Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Dheeraj Gupta (Dec 13)
- Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Nageswara Rao A.V.K (navk) (Dec 14)
- Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Dheeraj Gupta (Dec 14)
- Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Dheeraj Gupta (Dec 16)
- Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Nageswara Rao A.V.K (navk) (Dec 16)
- Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Dheeraj Gupta (Dec 16)
- Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Dheeraj Gupta (Dec 18)
- Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Dheeraj Gupta (Dec 14)
- Re: Large Packet Drop with SNort-2.9.80 as compared to Snort-2.9.7.6 Nageswara Rao A.V.K (navk) (Dec 14)