---
title: Invalid URL Regular Expression
description: A Perl-compatible or ECMAScript-compatible (IIS) regular expression to parse valid request URLs. The agent rejects requests to invalid URLs with HTTP 403 Forbidden status without further processing.
component: web-agents
version: 2025.11
page_id: web-agents:properties-reference:com.forgerock.agents.agent.invalid.url.regex
canonical_url: https://docs.pingidentity.com/web-agents/2025.11/properties-reference/com.forgerock.agents.agent.invalid.url.regex.html
---

# Invalid URL Regular Expression

A Perl-compatible or ECMAScript-compatible (IIS) regular expression to parse valid request URLs. The agent rejects requests to invalid URLs with HTTP 403 Forbidden status without further processing.

For example, to filter out URLs containing a list of characters and words such as `…​ %00-%1f, %7f-%ff, %25, %2B, %2C, %7E`, configure the following regular expression:

`com.forgerock.agents.agent.invalid.url.regex=http[s]?:\/\/[^\/]+\/(?i)(?!\\|[?]\/\/|\.\/|[?]\/\.|\/\|\\.|~|[?]%2d|%20|[?]%[0-1][0-9a-f]|%[7-9a-f][0-9a-f]|[?]%25)[?]?.`

Default: Empty

|                    |                                                                              |
| ------------------ | ---------------------------------------------------------------------------- |
| Property name      | `com.forgerock.agents.agent.invalid.url.regex`   Introduced in Web Agent 4.x |
| Function           | URL handling                                                                 |
| Type               | String                                                                       |
| Bootstrap property | No                                                                           |
| Required property  | No                                                                           |
| Restart required   | No                                                                           |
| AM console         | Tab: `Miscellaneous (From AM 7)`Title: `Invalid URL Regular Expression`      |