[squid-users] http_port intercept: squid 3.1.20 VS 3.5.23.

[Thomas Martin]

Hello,

I'm having trouble to make Squid 3.5.23 work like Squid 3.1.20 does.

Here is my setup:
  <clients>     |                  <router>                      |
<squid proxy>
10.0.0.Y/24    | 10.0.0.254/24 <-> 10.100.0.254/24 |   10.100.0.100/24

The goal was to have the <squid proxy> as a transparent HTTP proxy for
all <clients>; it was achieved few years ago using Squid 3.1.20.


- <clients> have one network interface and 10.0.0.254 as default gateway

- <router> is:
-- obviously forwarding packets,
-- owning the ADSL,
-- doing the transparent redirection of <clients> to <squid proxy> using NAT:
-A PREROUTING -s 10.100.0.100 -i dmz -p tcp -m state --state NEW -m
tcp --dport 80 -j ACCEPT
-A PREROUTING -s 10.0.0.Y/32 -p tcp -m state --state NEW -m tcp
--dport 80 -j DNAT --to-destination 10.100.0.100:3128

- <squid proxy> have one network interface and 10.100.0.100 as default gateway.
Squid's configuration is quite simple:
http_access allow all
http_port 0.0.0.0:3128 intercept
cache_mgr ...
cache_mem ...
...


This is working perfectly fine with Squid 3.1.20.


But now that I have upgraded <squid proxy>  to 3.5.23 (from Debian
Wheezy to Stretch) this is not working anymore.

The test I'm using is simple: "curl  http://www.google.fr -I" from <clients>.

<clients> are getting 403 returned by <squid proxy> 3.5.23.
In Squid's logs I had: "ERROR: No forward-proxy ports configured.".
After reading Squid docs, forums, mailing, list, etc, I tried to add
another http_port:
http_access allow all
http_port 0.0.0.0:3128 intercept
http_port 0.0.0.0:8080

But it does not work either, Squid seems to loop internally with a lot
a log access_log (even for one request only).


I feel like I missed something obvious, I spent quite some time to
understand but had no luck.
Am I missing something ?

When I was reading on the web, some users claimed that I should have
two network interfaces between <router> and <squid proxy> ?
If that true, why is it working perfectly with Squid 3.1.20 ?


Any clue will be appreciated.

Thanks.