M4 Header Transformation Rules Groups

Header Transformation Rules are available in the Routing section.

Press ADD NEW to create Header Transformation Rules Group.

The image below shows which headers are possible to modify.

Depending on the header, it is possible to:

• Forward without changes - no changes to headers.
• Transform and forward - modify the current header.
• Transform existing, generate if missing - modify the current header if it exists. If it does not exist, a header will be generated.
• Overwrite - drop the original header if it exists and create a new one.
• Drop - removes the header.

It is also possible to add a custom header to the empty header field.

Regexp Transformation is used to modify headers.

See also

• M4 Regexp Examples
• M4 Kamailio Transformations
• M4 Source Transformation
• M4 Destination Transformation
• Check your regexp: http://regex101.com/