When the Rule Type selected is Replace Header the following describes the options available.

Rule Name

This is for a textbox to enter the name of the rule.

Header Field

This is for a textbox to enter the header name field where the substitution should take place.

Match String

The pattern that is to be matched.

Value of Header Field to be replaced

This is for a textbox to enter the value of the header field to be replaced.

Perform If Flag Set

Only execute this rule if the specified flag is set.

The flag is set by a different rule. For a more detailed explanation of flags please refer to the Content Matching section.

Perform If Flag is NOT Set

Only try to execute this rule if the specified flag is not set.