[squid-users] adding cache_control = nocache to http request using squid transparent proxy

[ngtech1ltd at gmail.com]

Hey Amos,

I support what you wrote and I do not know why the service provider wants this but there are some cases
which there is a need to lower the cache ratio of the clients.
Usually fast service is what ISPs want but there are couple use cases that I have seen which makes sense to somehow
try to disable cache in the client side.
In these specific cases the relationship of the ISP and the client should be fully understood by both side
and the ISP should OVER COMMIT their services to the client to compensate for the client limitations.
I would assume it should be some 50-100% of the package over commit.
In the last years I have seen that 1080HD videos uses usually 3Mbps VBR in cases of real time transcoding of the video
( both in server and client side ) while 6Mbps in CBR for the exact same pre-transcoded videos.
(which reduces the client side CPU and device requirements).

So, in case I would have couple CDNs pushing data to my network while the one is overloading my clients current hardware
There is a right to push back this CDN performance since he somehow in-directly forces my clients to  upgrade their hardware.

To my understanding many ISPs and CDNs won't see their actions to give better service coverage as bad
but what's next? We won't be able to snoop in our noses between commercials that are popping into 
our screen or eyes or head?

I just put this really faint conversation in my head:
Son: ohh my head hurts dad!
Dad: Who hit you?
Son: I don't know, I was sitting Infront of the **device** and the video was 4k fps.
Dad: You should use a lower image fps rendering, in my days we used to watch matrix in 15-30 fps and it was fun.

Hope It Helps to give someone a smile.

Eliezer

----
Eliezer Croitoru
NgTech, Tech Support
Mobile: +972-5-28704261
Email: ngtech1ltd at gmail.com
Web: https://ngtech.co.il/
My-Tube: https://tube.ngtech.co.il/

-----Original Message-----
From: squid-users <squid-users-bounces at lists.squid-cache.org> On Behalf Of Amos Jeffries
Sent: Wednesday, 27 July 2022 3:46
To: squid-users at lists.squid-cache.org
Subject: Re: [squid-users] adding cache_control = nocache to http request using squid transparent proxy

On 27/07/22 07:52, muhanad wrote:
> Hello
> 
> I am trying to edit the header of http headers to set the cache_control 
> option to " no-cache" to prevent users from being able to cache the 
> contents

This will not do what you think it does.

The "no-cache" control actually *enables* caching by recipients. It just 
requires a quick revalidation check before the cached content is used.


> even if they are using any type of caching engines. the squid 
> proxy will work in a transparent mode. The traffic is originated from 
> one of our CDNs,

This does not make sense. Just publish the Squid machine IP in DNS 
instead of the CDN server IP. No need for interception.


> also the connection is direct between the clients and 
> the CDN servers, thus the proxy will work in transparent mode with IP 
> spoofing so the in the header the IP address is stays the IP address of 
> the client and  not the proxy server.

This may not do what you think it does. When traffic is arriving *from* 
Internet the source-IP indicates which route to deliver the response 
packets. You do not want the origin server(s) bypassing Squid on the TCP 
SYNACK packets - that will break all traffic.


> PS: We are an ISP company based in Iraq, Baghdad and we are trying to 
> prevent the clients from caching all HTTP data.
> 

Why? This is typically a very bad idea.

All it does is:
  * lower the amount of bandwidth available to your clients
    - given them a bad service/experience.
  * increase the traffic delays across your network
    - even worse service/experience.
  * encourage other ISP to erase the cache limitations on traffic from 
your servers even on traffic where it is correct
    - even worse service/experience.


Even if you are charging clients for bandwidth used. You want to be able 
to service *more* clients as quickly as possible, not scare them away 
with a bad service.


HTH
Amos
_______________________________________________
squid-users mailing list
squid-users at lists.squid-cache.org
http://lists.squid-cache.org/listinfo/squid-users