Add video and Settings docs for Packet Capture features (#3060)

Author: philrz

apps/zui/docs/features/Packet-Captures.md

@@ -0,0 +1,67 @@
+---
+sidebar_position: 2
+---
+
+# Packet Captures
+
+The video below describes Zui's features for working with packet capture
+([pcap](https://en.wikipedia.org/wiki/Pcap)) data.
+
+Areas covered include:
+* The role of [Brimcap](https://github.com/brimdata/brimcap) to generate [Zeek](https://zeek.org/) and [Suricata](https://suricata.io/) summary logs from the pcap
+* Views in Zui's **Detail** pane that show:
+   * Correlations between different Zeek events and Suricata alerts
+   * Ladder diagrams to summarize connection lifecycle
+   * Observed file payload activity
+* Extracting flows using Zui's **Download Packets** button
+* Right-click menu options for querying values in [VirusTotal](https://www.virustotal.com/) and/or [`whois`](https://en.wikipedia.org/wiki/WHOIS)
+* Zui [**Settings** for pcap features](#settings)
+
+<iframe width="560" height="315" src="https://www.youtube.com/embed/eMzljqxASVA?si=GQnKRCpKLjc1SUAq" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+
+## Settings
+
+The following sections provide additional detail on the pcap-specific
+customizations that can be configured in Zui's **Settings**.
+
+![Settings - Packet Captures](../media/Settings-Packet-Captures.png)
+
+### Folder For Extracted pcaps
+
+When the **Download Packets** button is pressed, the timestamp and duration
+details of the underlying Zeek `conn` record are queried in Brimcap's pcap
+index to extract the packet data for that single flow. By default, the
+generated pcap file is stored in an OS-specific
+[temporary directory](../support/Filesystem-Paths.md#temporary-storage).
+If you'd prefer to specify an alternate directory (such as if gathering up pcap
+evidence for an investigation), clicking the **Choose Folder** button allows
+the selection of any other writable destination folder to which Zui should
+write extracted pcap flows.
+
+### Local Suricata Rules Folder
+
+By default, the Suricata software that ships with Zui applies the
+[Emerging Threats Open](https://community.emergingthreats.net/) rule set when
+generating alert events from imported pcap data. This rule set is updated each
+time Zui is launched and connected to the Internet.
+
+If you've downloaded one or more additional rule sets that you'd like to
+apply, store one or more rule files in a folder on your workstation, then
+click the **Choose Folder** button and select the folder. The rules in these
+additional files will be included alongside the default Emerging Threats Open
+rules whenever Zui updates its Suricata rules.
+
+### Brimcap YAML Config File
+
+The Zeek and Suricata analyzers that are embedded with Zui via Brimcap are
+configured with defaults that we hope will serve common pcap use cases.
+However, if for some reason you require customizations beyond those in the
+settings described above, need to use different release versions of these
+analyzers, or make use of other analyzers that generate summary logs from pcaps,
+[this Brimcap article](https://github.com/brimdata/brimcap/wiki/Custom-Brimcap-Config)
+describes how to create such a custom configuration. The article shows how to
+create the configuration in a YAML file. Once you've successfully created and
+tested the YAML configuration with Brimcap, click the **Choose File** button,
+browse to the YAML file, and select it. Once set, any pcaps you drag into
+Zui will be submitted for analysis based on your Brimcap YAML config rather
+than the default Zeek and Suricata software that shipped with Zui.

apps/zui/docs/media/Settings-Packet-Captures.png

@@ -18,21 +18,29 @@ export function activateBrimcapConfigurations() {
         defaultValue: "",
         helpLink: {
           label: "docs",
-          url: "https://github.com/brimdata/brimcap/wiki/Custom-Brimcap-Config",
+          url: "https://zui.brimdata.io/docs/features/Packet-Captures#brimcap-yaml-config-file",
         },
       },
       [suricataLocalRulesPropName]: {
         name: suricataLocalRulesPropName,
         type: "folder",
         label: "Local Suricata Rules Folder",
         defaultValue: "",
+        helpLink: {
+          label: "docs",
+          url: "https://zui.brimdata.io/docs/features/Packet-Captures#local-suricata-rules-folder",
+        },
       },
       [pcapFolderPropName]: {
         name: pcapFolderPropName,
         type: "folder",
         label: "Folder For Extracted pcaps",
         defaultValue: "",
         placeholder: "Default OS tmpdir",
+        helpLink: {
+          label: "docs",
+          url: "https://zui.brimdata.io/docs/features/Packet-Captures#folder-for-extracted-pcaps",
+        },
       },
     },
   })