diff --git a/doc/sphinx/performance/ignoring-traffic.rst b/doc/sphinx/performance/ignoring-traffic.rst new file mode 100644 index 0000000000..6e6f0db9f5 --- /dev/null +++ b/doc/sphinx/performance/ignoring-traffic.rst @@ -0,0 +1,46 @@ +Ignoring Traffic +================ + +In some cases there are reasons to ignore certain traffic. Maybe a +trusted host or network, or a site. This document lists some +strategies for ignoring traffic. + +capture filters (BPF) +--------------------- + +Through BPFs the capture methods pcap, af-packet and pf_ring can be +told what to send to Suricata, and what not. For example a simple +filter 'tcp' will only send tcp packets. + +If some hosts and or nets need to be ignored, use something like "not +(host IP1 or IP2 or IP3 or net NET/24)". + +pass rules +---------- + +Pass rules are Suricata rules that if matching, pass the packet and in +case of TCP the rest of the flow. They look like normal rules, except +that instead of 'alert' or 'drop' they start with 'pass'. + +Example: + +:: + + pass ip 1.2.3.4 any <> any any (msg:"pass all traffic from/to 1.2.3.4"; sid:1;) + +A big difference with capture filters is that logs such as http.log +are still generated for this traffic. + +suppress +-------- + +Suppress rules can be used to make sure no alerts are generated for a +host. This is not efficient however, as the suppression is only +considered post-matching. In other words, Suricata first inspects a +rule, and only then will it consider per-host suppressions. + +Example: + +:: + + suppress gen_id 0, sig_id 0, track by_src, ip 1.2.3.4 diff --git a/doc/sphinx/performance/index.rst b/doc/sphinx/performance/index.rst index 9fc1cd4af9..b06bee6f58 100644 --- a/doc/sphinx/performance/index.rst +++ b/doc/sphinx/performance/index.rst @@ -10,3 +10,4 @@ Performance rule-profiling runmodes tcmalloc + ignoring-traffic