Segue um trecho da documentação disponível na web; a diretiva ServerTokens configura quais informações relativas à descrição do servidor e do respectivo sistema operacional e dos módulos são enviadas no cabeçalho de resposta. Ver os exemplos abaixo ( http://httpd.apache.org/docs/current/mod/core.html#servertokens ) :
"This directive controls whether Server response
header field which is sent back to clients includes a
description of the generic OS-type of the server as well as
information about compiled-in modules.
ServerTokens Full (or not specified)
Server sends (e.g.):
Server: Apache/2.4.2
(Unix) PHP/4.2.2 MyMod/1.2
ServerTokens Prod[uctOnly]
Server sends (e.g.):
Server:
Apache
ServerTokens Major
Server sends (e.g.):
Server:
Apache/2
ServerTokens Minor
Server sends (e.g.):
Server:
Apache/2.4
ServerTokens Min[imal]
Server sends (e.g.):
Server:
Apache/2.4.2
ServerTokens OS
Server sends (e.g.):
Server: Apache/2.4.2
(Unix)
This setting applies to the entire server, and cannot be
enabled or disabled on a virtualhost-by-virtualhost basis."