15
Chapter 3
Web Proxy Caching
Alternates are identified by header information. You can configure Traffic Server to cache all alternates
according to a particular header. For example, if you tell Traffic Server to vary on the
User-Agent
header,
Traffic Server caches all the different user-agent versions of documents it encounters. You configure the
caching of alternates in the Variable Content section of the Cache page in Traffic Manager’s Configure
mode.
To cache or not to cache?
.
The following table lists the HTTP caching directives that Traffic Server follows.
NNTP
You can limit article caching to specific news groups. See
Blocking particular groups‚ on
page 18
.
FTP
You can specify never-cache rules for specific types of FTP documents in the
cache.config
file. See
cache.config‚ on page 162
.
HTTP
Traffic Server responds to caching directives from clients and origin servers, as well as
configurable options in Traffic Manager and the
cache.config
file.
Directive source
Caching directives
administration
options
Traffic Server has the following administration options for caching:
•
Configure Traffic Server not to cache objects with URLs containing the
following:
?
;
/cgi
end in
.asp
•
Configure Traffic Server not to cache objects served in response to the
Cookie
:
header.
•
Use never-cache rules in the
cache.config
file. Refer to
cache.config‚ on
page 162
.
client
Traffic Server does not cache objects with the following request headers. Note that
some of these directives can be overridden by Traffic Server administration options.
•
Cache-Control: no-store header
•
Cookie: header
•
Authorization: header
origin server
Traffic Server does not cache objects with the following response headers. Note that
some of these directives can be overridden by Traffic Server administration options.
•
Cache-Control: no-store
•
www-Authenticate: header
•
Set-Cookie: header
•
Cache-Control: no-cache header
•
Pragma: no-cache header
•
Expires: header with value of 0 (zero) or a past date
