I'm trying to conditionally remove a proxy header but this doesn't appear to be allowed using an "if". Ideally it would look something like this where $external_traffic is either 0 or 1:

if ($external_traffic) {
...
proxy_hide_header WWW-Authenticate; # Remove negotiate header
...
}

My workaround is to set up another site with proxy_hide_header set and do a redirect to it inside the if instead but that seems messy.

if ($external_traffic) {
...
rewrite ^ https://external.testdomain.com$request_uri break;
...
}

Is there a better way to do this?

Thanks,
Neil