waf http-request-flood-prevention-rule

Use this command to limit the maximum number of HTTP requests per second coming from any client to a specific URL on one of your protected servers.

The FortiWeb appliance tracks the requests using a session cookie. If the count exceeds the request limit, FortiWeb performs the specified action.

To apply this rule, include it in an application-layer DoS-prevention policy. This feature is effective only when http-session-management {enable | disable} is enabled in the inline protection profile that uses the parent DoS-prevention policy.

To use this command, your administrator account’s access control profile must have either w or rw permission to the wafgrp area. For details, see Permissions.

Syntax

config waf http-request-flood-prevention-rule

edit "<rule_name>"

set access-limit-in-http-session <limit_int>

set action {alert | alert_deny | block-period | deny_no_log}

set bot-recognition {captcha-enforcement | real-browser-enforcement | disable}

set max-attempt-times <attempts_int>

set validation-timeout <seconds_int>

set block-period <seconds_int>

set severity {High | Medium | Low | Info}

set trigger-policy "<trigger-policy_name>"

set mobile-app-identification {disabled | mobile-token-validation}

set bot-confirmation {enable | disable}

end

Variable	Description	Default
"<rule_name>"	Enter the name of a new or existing rule. The maximum length is 63 characters. To display the list of existing rules, enter: `edit ?`	No default.
access-limit-in-http-session <limit_int>	Enter the maximum number of HTTP connections allowed per second from the same client. The valid range is 0–4,096. To disable the limit, enter `0`.	0
action {alert \| alert_deny \| block-period \| deny_no_log}	Select one of the following actions that the FortiWeb appliance will perform when the count exceeds the limit: `alert`—Accept the request and generate an alert email and/or log message. `alert_deny`—Block the request (or reset the connection) and generate an alert email and/or log message. You can customize the web page that FortiWeb returns to the client with the HTTP status code. For details, see system replacemsg. `block-period`—Block subsequent requests from the client for a number of seconds. Also configure block-period <seconds_int>. Note: If FortiWeb is deployed behind a NAT load balancer, when using this option, you must also define an X-header that indicates the original client’s IP (see waf x-forwarded-for). Failure to do so may cause FortiWeb to block all connections when it detects a violation of this type. `deny_no_log`—Deny a request. Do not generate a log message. Caution: This setting will be ignored if monitor-mode {enable \| disable} is enabled. Note: Logging and/or alert email will occur only if enabled and configured. For details, see log disk and log alertMail. Note: If you select an auto-learning profile with this rule, you should select `alert`. If the `action` is `alert_deny`, for example, the FortiWeb appliance will block the request or reset the connection when it detects an attack, resulting in incomplete session information for the auto-learning feature. For details about auto-learning requirements, see waf web-protection-profile autolearning-profile.	`alert`
bot-recognition {captcha-enforcement \| real-browser-enforcement \| disable}	Enable to return a JavaScript to the client to test whether it is a web browser or automated tool when it exceeds the rate limit. If the client either fails the test or does not return results before the timeout specified by validation-timeout <seconds_int>, FortiWeb applies the specified action. If the client appears to be a web browser, FortiWeb allows the client to exceed the rate limit. Disable this option to apply the rate limit regardless of whether the client is a web browser (for example, Firefox) or an automated tool (for example, `wget`).	`disable`
max-attempt-times <attempts_int>	If `captcha-enforcement` is selected for bot-recognition {captcha-enforcement \| real-browser-enforcement \| disable}, enter the maximum number of attempts that a client may attempt to fulfill a CAPTCHA request. The valid range is 1–5. Available only when `captcha-enforcement` is selected for `bot-recognition`.	3
validation-timeout <seconds_int>	Specify the maximum amount of time (in seconds) that FortiWeb waits for results from the client for Real Browser Enforcement. The valid range is 5–30.	20
block-period <seconds_int>	If `action` is `block-period`, type the number of seconds that the connection will be blocked. This setting applies only if `action` is block-period. The valid is from 1 to 10,000 seconds.	`60`
severity {High \| Medium \| Low \| Info}	Select the severity level to use in logs and reports generated when a violation of the rule occurs.	Medium
trigger-policy "<trigger-policy_name>"	Enter the name of the trigger to apply when this rule is violated. For details, see log trigger-policy. The maximum length is 63 characters. To display the list of existing trigger policies, enter: `set trigger ?`	No default.
mobile-app-identification {disabled \| mobile-token-validation}	Disabled: Disable not to carry out the mobile token verification. Mobile Token Validation: Requires the client to use mobile token for verification. To apply mobile token validation, you must enable Mobile App Identification in waf web-protection-profile inline-protection	`Disabled`
bot-confirmation {enable \| disable}	Enable to choose how to verify users when the rules of bot detection are triggered.	`Disabled`

Example

This example illustrates a rule that imposes a two-minute blocking period on clients that exceed the set request limit.

config waf http-request-flood-prevention-rule

edit "Web Portal HTTP Request Limit"

set access-limit-in-http-session 10

set action block-period

set block-period 120

set severity Medium

set trigger-policy "Server_Policy_Trigger"

end