---
title: Fields reference · Cloudflare Ruleset Engine docs
description: The Cloudflare Rules language supports different types of fields such as:
lastUpdated: 2025-01-17T12:22:49.000Z
source_url:
  html: https://fd082a90.preview.developers.cloudflare.com/ruleset-engine/rules-language/fields/index.md
  md: https://fd082a90.preview.developers.cloudflare.com/ruleset-engine/rules-language/fields/
---

The Cloudflare Rules language supports different types of fields such as:

* Request fields that represent the basic properties of incoming requests, including specific fields for accessing request headers, URI components, and the request body.
* Dynamic fields that represent computed or derived values, typically related to threat intelligence about an HTTP request.
* Response fields that represent the basic properties of the received response.
* Raw fields that preserve the original request values for later evaluations.

Refer to the [Fields reference](https://developers.cloudflare.com/ruleset-engine/rules-language/fields/reference/) for the list of available fields.

## Differences from Wireshark display fields

Most fields supported by the Cloudflare Rules language use the same naming conventions as [Wireshark display fields](https://www.wireshark.org/docs/wsug_html_chunked/ChWorkBuildDisplayFilterSection.html). However, there are some subtle differences between Cloudflare and Wireshark:

* Wireshark supports [CIDR (Classless Inter-Domain Routing) notation](https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing) for expressing IP address ranges in equality comparisons (`ip.src == 1.2.3.0/24`, for example). Cloudflare does not.

  To evaluate a range of addresses using CIDR notation, use the `in` [comparison operator](https://developers.cloudflare.com/ruleset-engine/rules-language/operators/#comparison-operators) as in this example: `ip.src in {1.2.3.0/24 4.5.6.0/24}`.

* In Wireshark, `ssl` is a protocol field containing hundreds of other fields of various types that are available for comparison in multiple ways. However, in the Rules language `ssl` is a single Boolean field that indicates whether the connection from the client to Cloudflare is encrypted.

* The Cloudflare Rules language does not support the `slice` operator.
