why no cache without "Cookie: TRACKID"?

[xiaxueyi]

ver: lighttpd-1.4.21.modcache.v.1.6.3

config:
cache.support-queries = "enable"
cache.ignore-reload = "enable"
cache.fetchall-for-range-request = "enable"
cache.bases = ("/home/cache")
cache.refresh-pattern = (
"." => "525600 fetchall-for-range-request"
)
cache.domains = ("a.com")
$HTTP["host"] =~ "a.com"{
proxy.server = ( "/" =>
(
( "host" => "1.1.1.1", "port" => 80 ) # real
backend http server ip and port
)
)
proxy.worked-with-mod-cache = "enable"
}



when client send:
GET /test.txt HTTP/1.0
Accept: */*
Accept-Language: zh-cn
UA-CPU: x86
User-Agent: Mozilla/4.0
Host: a.com
Connection: Close
Range: bytes=10-20
Cache-Control: no-cache
Pragma: no-cache

a.txt won't be cached



when client send:

GET /test.txt HTTP/1.0
Accept: */*
Accept-Language: zh-cn
UA-CPU: x86
User-Agent: Mozilla/4.0
Host: a.com
Connection: Close
Range: bytes=10-20
Cache-Control: no-cache
Pragma: no-cache
Cookie: TRACKID=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

a.txt will be cached

why?
thank you

[Hongyu]

when the request has no "Cookie: " header, your web server will reply with "Set-Cookie:" response

response with "Set-Cookie" header should not be cached