Issue #91: Document localhost proxying. (#104)

Author: ninjeeter

.markdownlint.json

@@ -6,5 +6,6 @@
   "fenced-code-language": false,
   "no-duplicate-heading": false,
   "ol-prefix": false,
-  "no-trailing-punctuation": false
+  "no-trailing-punctuation": false,
+  "heading-increment": false
 }

.vitepress/sidebars/guides.ts

@@ -24,6 +24,10 @@ export const guidesSidebar: DefaultTheme.SidebarItem[] = [
         {
             text: 'Running in Docker',
             link: '/guides/user_guide/docker'
+        },
+        {
+            text: 'Proxying Local Traffic',
+            link: '/guides/user_guide/proxy_local'
         }
     ]
 },

src/guides/index.md

@@ -5,6 +5,7 @@
 - **[Installation](./user_guide/installation.md)** - step-by-step instructions on downloading Caido.
 - **[Caido on a VPS](./user_guide/vps.md)** - running Caido on a Virtual Private Server.
 - **[Caido on Dockerhub](./user_guide/docker.md)** - running Caido in a Docker container.
+- **[Proxying Local Traffic](./user_guide/proxy_local.md)** - capturing localhost traffic.
 
 ## Contributions
 

src/guides/user_guide/proxy_local.md

@@ -0,0 +1,52 @@
+# Proxying Local Traffic
+
+When running a web page or web application locally, Caido may not be capturing the traffic due to what is known as **implicit bypass rules**. These rules match URLs whose host portion is either a localhost name or a link-local IP literal. If a match is detected - requests will not be routed through a proxy and are instead sent directly.
+
+Implicit bypass rules match against the following:
+
+- localhost
+
+- *.localhost [::1]
+
+- 127.0.0.1/8
+
+- 169.254/16
+
+- [FE80::]/10
+
+## Resolutions
+
+If you are having issues proxying localhost traffic - try the following:
+
+#### Use lvh.me:
+
+This domain name resolves to 127.0.0.1.
+
+- [http://lvh.me/](http://lvh.me/)
+
+#### Edit the proxy bypass rules:
+
+By default, localhost may be included as a proxy bypass address within the list of hosts used by your system/browser/extension. This can be overwritten by supplying `<-loopback>` (_the `-` character inverts the rule_).
+
+- Launch Chrome via the terminal using:
+
+```
+google-chrome --proxy-server=127.0.0.1:8080` --proxy-bypass-list="<-loopback>"
+```
+
+::: tip
+If you customized the listening address/port of Caido - replace the values in the command to match. Click [here](https://chromium.googlesource.com/chromium/src/+/HEAD/net/docs/proxy.md#Overriding-the-implicit-bypass-rules) for more information.
+:::
+
+- If you are using the FoxyProxy browser extension: select `Options` and add `<-loopback>` to the `Global Exclude` list.
+- In general, this bypass list can be modified in the proxy settings of different systems/browsers/extensions by supplying `<-loopback>` to the hosts list. This input field is usually accompanied with a title or description that includes key-terms/keywords such as: `except these addresses`, `no-proxy for`, `exclude`, etc.
+
+#### Use the Firefox Browser:
+
+::: info
+If proxying localhost traffic is not working in Firefox as well:
+
+- Navigate to `about:config`.
+- Set `network.proxy.allow_hijacking_localhost` to `true`.
+- Restart Firefox.
+:::