For HTTP-headers there seems to be a conversion. From HTTP::Headers (used by HTTP::Request::Common via HTTP::Message):

ON-CANONICALIZED FIELD NAMES
The header field name spelling is normally canonicalized including the '_' to '-' translation. There are some application where this is not appropriate. Prefixing field names with ':' allow you to force a specific spelling. For example if you really want a header field name to show up as "foo_bar" instead of "Foo-Bar", you might set it like this:

$h->header(":foo_bar" => 1);

Assuming, you want to post a list of variables, do transfer them as content (application/x-www-form-urlencoded), not as HTTP-headers.
Please check POST method invocation parameters (order/names) or post the specific lines, where you're creating the POST request, for further analysis.

In reply to Re: POST fieldnames with underscores by Perlbotics
in thread POST fieldnames with underscores by BernieC

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