----------------cách 1------------------
# sub vcl_recv {
#     if (req.restarts == 0) {
#       if (req.http.x-forwarded-for) {
#           set req.http.X-Forwarded-For =
#               req.http.X-Forwarded-For ", " client.ip;
#       } else {
#           set req.http.X-Forwarded-For = client.ip;
#       }
#     }
        if (req.http.user-agent ~ "Hotbar") {
                return(synth(403,"Not allowed."));
       }
#     if (req.request != "GET" &&
#       req.request != "HEAD" &&
#       req.request != "PUT" &&
#       req.request != "POST" &&
#       req.request != "TRACE" &&
#       req.request != "OPTIONS" &&
#       req.request != "DELETE") {
#         /* Non-RFC2616 or CONNECT which is weird. */
#         return (pipe);
#     }


--------------cách 2---------------
# sub vcl_recv {
#     if (req.restarts == 0) {
#       if (req.http.x-forwarded-for) {
#           set req.http.X-Forwarded-For =
#               req.http.X-Forwarded-For ", " client.ip;
#       } else {
#           set req.http.X-Forwarded-For = client.ip;
#       }
#     }
#        if (req.http.user-agent ~ "Hotbar") {
#                return(synth(403,"Not allowed."));
#        }
#     if (req.request != "GET" &&
#       req.request != "HEAD" &&
#       req.request != "PUT" &&
#       req.request != "POST" &&
#       req.request != "TRACE" &&
#       req.request != "OPTIONS" &&
#       req.request != "DELETE") {
#         /* Non-RFC2616 or CONNECT which is weird. */
#         return (pipe);
#     }