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Myra Online Help Updated · 25 Aug 2026

URI substitution with query strings

A WAF rule with the URI Substitution action allows you to rewrite the requested URI and control the query parameters.

example_substitue_EN

Actions: Remove a query string and substitute the URI

For example, proceed as follows to replace the query parameter foo1 and keep foo2 and foo3:

  • ► Select Request as the request method.
  • ► Add the Remove Query String action.
  • ► Enter foo1 as the value.
  • ► Add the URI Substitution action.
  • ► Enter /geheim/(.*) as the search pattern.
  • ► Enter /geheimesuche/$1?foo1=pepe& as the value.

Note

$1 stands for the first captured group of the regular expression. An & at the end appends the remaining query parameters.