[squid-users] Reg - Squid can cache the chrome OS updates.

[Amos Jeffries]

On 26/06/2015 4:36 p.m., Squid List wrote:
> Hi,
> 
> Is the Squid can cache Microsoft Updates and IOS Updates?
> 
> If its cache means, please help me out for cache Chrome OS updates in
> latest squid version that is installed in CentOS 6.6.

The short answer (FWIW):

Squid can (and does) cache any HTTP content which is cacheable. With the
exception of 206 responses and PUT request payloads.


The long answer:

Whether the cached content is used depends entirely on what the client
requests. It has the power to request that cached content be ignored.

Whether content is cacheable depends entirely on what the server
delivers. It has the power to place limits on cache times up to and
including stating an object is already stale (ie not usefully cached).

There are also some mechanisms which when used MAY make content
completely untrustworthy or and uncacheable:
* connection based authentication (NTLM, Negotiate)
* traffic interception (NAT, TPROXY, SSL-Bump)
* broken Vary headers (though this causes caching when it shouldn't)
*


I hope that explains why you wont get a clear simple answer to your
question.

To help any further we will need information about;
- what Squid version you are using (if its not the latest 3.5 please try
an upgrade),
- how its configured (squid.conf without the comment lines please),
- how its being used (explicit forward-, reverse-, or interception proxy)
- what exactly the request messages you are trying to make into HITs are
("debug_options 11,2" produces a traces of those),
- what response messages the server is delivering on the MISS (the same
11,2 trace)
- what Squid is logging for them (access.log entries)

Amos