vcl_recv的默认配置：

sub vcl_recv {

if (req.method == “PRI”) {

/ We do not support SPDY or HTTP/2.0 /

return (synth(405));

}

if (req.method != “GET” &&

req.method != “HEAD” &&

req.method != “PUT” &&

req.method != “POST” &&

req.method != “TRACE” &&

req.method != “OPTIONS” &&

req.method != “DELETE”) {

/ Non-RFC2616 or CONNECT which is weird. /

return (pipe);

}

if (req.method != “GET” && req.method != “HEAD”) {

/ We only deal with GET and HEAD by default /

return (pass);

}

if (req.http.Authorization || req.http.Cookie) {

/ Not cacheable by default /

return (pass);

}

return (hash);

}

}

Client Side：

vcl_recv, vcl_pass, vcl_hit, vcl_miss, vcl_pipe, vcl_purge, vcl_synth, vcl_deliver

vcl_recv：

hash：vcl_hash

pass: vcl_pass

pipe: vcl_pipe

synth: vcl_synth

purge: vcl_hash –> vcl_purge

vcl_hash：

lookup：

hit: vcl_hit

miss: vcl_miss

pass, hit_for_pass: vcl_pass

purge: vcl_purge

Backend Side：

vcl_backend_fetch, vcl_backend_response, vcl_backend_error