Thu Nov 23 16:36:19 EST 2017
the sensor. The snort config file has no rules, but both the stream4
frag2 preprocessors were on. I alternated between running the two=20
different snort processes.The rate of injection was: 591379.9 bytes/sec=20
4.51 megabits/sec 2401 packets/sec as reported by tcpreplay
I did this 3 times with each Snort 2.1.3rc1 with libpcap 0.7.2 library
Snort 2.1.3rc2 with libpcap 0.8.3 library.=20
Snort 2.1.3rc1 with libpcap 0.7.2 library:
Attempt 1: Snort analyzed 970415 out of 970415 packets, dropping
Attempt 2: Snort analyzed 975566 out of 975566 packets, dropping
Attempt 3: Snort analyzed 978249 out of 978249 packets, dropping
Total: 2924230 captured, out of 3,000,000 sent.=20
Snort 2.1.3rc2 with libpcap 0.8.3 library:
Attempt 1: Snort analyzed 999706 out of 1000000 packets, dropping=20
Attempt 2: Snort analyzed 1000000 out of 1000000 packets, dropping=20
Attempt 3:Snort analyzed 1000000 out of 1000000 packets, dropping=20
Total: 2999706 captured out of 3,000,000.
So, not only is libpcap 0.8.3 more efficient, it also accurately reports
packets dropped (see below), while Snort with libpcap 0.7.2 had no
of dropped packets, at least on Solaris.
I did a few more tests with libpcap 0.8.3:
First turning on the rules i normally use, about 2/3 of the current=20
Snort analyzed 985212 out of 1000000 packets, dropping 14788(1.479%)=20
Snort analyzed 978054 out of 1000000 packets, dropping 21946(2.195%)=20
Snort analyzed 987043 out of 999996 packets, dropping 12953(1.295%)=20
*** This last one is interesting because it seems to have missed 4
somewhere, so maybe it's not AS honest as i thought
Then with the rules from above, turning up the rate to 7Mbps:
Snort analyzed 996595 out of 1000000 packets, dropping 3405(0.340%)=20
Snort analyzed 988972 out of 1000000 packets, dropping 11028(1.103%)=20
Not sure why it reports droping less packets at 7Mbps than at 4.5.
That's all the tests I ran thus far. If anyone has anything else to=20
suggest, I am willing to try it if I have some free time.
In the meantime, does anyone know any way to tune Solaris to make it
efficient at packet captures?
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