I would like to mask the version or remove the header altogether.
To change the 'Server:' http header, in your conf.py file:
import gunicorn
gunicorn.SERVER_SOFTWARE = 'Microsoft-IIS/6.0'
And use an invocation along the lines of gunicorn -c conf.py wsgi:app
To remove the header altogether, you can monkey-patch gunicorn by replacing its http response class with a subclass that filters out the header. This might be harmless, but is probably not recommended. Put the following in conf.py:
from gunicorn.http import wsgi
class Response(wsgi.Response):
def default_headers(self, *args, **kwargs):
headers = super(Response, self).default_headers(*args, **kwargs)
return [h for h in headers if not h.startswith('Server:')]
wsgi.Response = Response
Tested with gunicorn 18