Replace Header
- Last Updated: August 5, 2025
- 2 minute read
- LoadMaster
- LoadMaster GA
- Documentation
The Replace Header option matches a header based on its value and replaces its value with the one specified. This can be used on the client header going to the server, or on the server header going to the client.
Rule Name
This field is used for identification and should be named to help remember what the rule does in the Virtual Service.
Header Field
This is the name of the field that the substitution will be performed on.
Match String
Enter a pattern to match against the content of this header. If the content matches the pattern, the header value will be replaced. This follows regular expression rules.
Value of Header Field to be replaced
When the rule is matched, the value of the header will be replaced with this text. Regular expressions and back references can be used here to reuse part of the existing value.
\1 and \2 can be used as back reference marks in PCRE expressions. For example:
Match: /(path1)\/(path2)/
Edit: new-path-is-\2/\1
Expected output: new-path-is-path2/path1
Perform if Flag is Set
Only execute this rule if the specified flag is set.
The flag will have been set by a different rule.
Perform If Flag is NOT Set
Only try to execute this rule if the specified flag is not set.