Caido

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.

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 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.