[squid-users] Hint for howto wanted ...

Walter H. walter.h at mathemainzel.info
Mon Nov 28 13:02:21 UTC 2016


I think we aren't understanding each other ...

let me show what my system is now:

a few clients - not all¹ - have configured a proxy,
let's say with IP
this proxy is a CentOS 6.8 with squid 3.1.23
this proxy only decides which parent to use ...

¹ some clients must be able to use internet without a proxy, my computer
e.g. is blocked at the router to use internet and therefore must use the

one parent is a CentOS 6.8 with squid 3.5.20, which does ACL filtering,
SSL-bump, malware checking with ClamAV, let's say with IP

the other parent at a webhoster in another country is also a CentOS 6.8
with squid 3.4.14, which should only be used for geoblocked content,
nothing more ..., let's say with IP

the television has let's say

my public IP address at home is let's say

the iptables of remote-proxy has besides other web, mail, ... specific
things just this:

-A INPUT -s -m tcp -p tcp --dport 3128 -m state --state NEW -j
-A INPUT -m tcp -p tcp --dport 3128 -j DROP

just to prevent others using my proxy;

the first proxy has this in it's squid.conf

acl kaspersky-labs-net dst
always_direct allow kaspersky-labs-net

# specific for the television
acl apa-net dst
always_direct allow apa-net

acl tv-device src

cache_peer parent 3128 0 name=local-proxy proxy-only no-digest
cache_peer parent 3128 0 name=remote-proxy proxy-only no-digest

acl remote-domains dstdomain "/etc/squid/remote-domains-acl.squid"

cache_peer_access local-proxy deny remote-domains
cache_peer_access local-proxy deny tv-device

cache_peer_access remote-proxy allow remote-domains
cache_peer_access remote-proxy allow tv-device
cache_peer_access remote-proxy deny all

cache_peer_access local-proxy allow all

as you see this is a little bit complex:
- the remote proxy is only used by the television,
  because there is the prevention of geoblocking critical,
  and for a few domains;²
- some networks are accessed directly without filtering,
  this is because some clients are blocked to connect
  to internet directly, but can use a proxy, or there is a
  problem with self-signed certificates; and filling up the logs
  a 2nd time with 'CONNECT' doesn't really make a sense ...
- some clients must connect to the internet without a proxy,
  either because they cannot configured to use a proxy or
  they don't want to use a proxy;

this reduces the origin question:

how can I use a parent proxy, when doing SSL-bump without changing any
(in order not to have to configure SSL-bump a 2nd time on the remote proxy)


On Mon, November 28, 2016 11:18, Eliezer Croitoru wrote:
> Hey Walter,
> I am not sure you understand the direction of things or what I am aiming
> for.
> First if the client has CentOS 6.8 There are RPM's for newer versions
> which I am building manually for the public use.
> Second: You can simplify the picture from Intercepting traffic using the
> local squid into "route" the traffic in the IP level towards the remote
> proxy.
> You can open a gre tunnel or to use some kind of simple VPN service to
> tunnel between the client box to the 3.5.20 box.
> If you will route the clients traffic towards the proxy in the IP level
> you would be free from handling the 3.1.X proxy.
> You should prioritize your goals between:
> - Caching
> -  ACL
> - Others
> Once you will open your mind from resolving and issue and convert it into
> a second form which is functionality I think I would be able to assist
> you.
> What is missing from the 3.1.X proxy?
> Is the SSL BUMP missing?
> What iptables rules are you using on the client machine(3.1.X)?
> All the above matters to understand how to offer the right solution.
> Eliezer
> ----
> Eliezer Croitoru
> Linux System Administrator
> Mobile: +972-5-28704261
> Email: eliezer at ngtech.co.il
> -----Original Message-----
> From: Walter H. [mailto:walter.h at mathemainzel.info]
> Sent: Monday, November 28, 2016 10:59
> To: Eliezer Croitoru <eliezer at ngtech.co.il>
> Cc: squid-users at lists.squid-cache.org
> Subject: RE: [squid-users] Hint for howto wanted ...
> On Mon, November 28, 2016 06:56, Eliezer Croitoru wrote:
>> OK so the next step is:
>> Routing over tunnel to the other proxy and on it(which has ssl-bump)
>> intercept.
> by now only the 3.5.20 squid on the local VM does SSL-bump
>> If you have a public on the remote proxies which can use ssl-bump then
>> route the traffic to there using Policy Based routing.
> how do I configure this?
>> You can selectively route by source or destination IP addresses.
> by now the remote has in its iptables to only accept port 3128 from my
> home IP (IPv6 and IPv4), but the IPv4 at home changes several times a
> year; means it is not fix;
>> Now my main question is: Can't you just install 3.5 on the 3.1.23
>> machine and bump there?
> SSL bump and parent proxy together doesn't work, if this worked I wouldn't
> need the 3.1.23 machine at all ...
> the 3.1.23 machine has the other 2 proxies (3.4.14-remote and
> 3.5.20-local) as parent ...
> I should mention that the 3.5.20 box also has ClamAV (SquidClam) which
> does malware checking ...
> (the remote proxy can't run ClamAV)
>> How are you intercepting the connections? What are the iptables rules
>> you are using?
> the client have configured the 3.1.23 squid box as proxy
>> What OS are you running on top of the Squid boxes?
> all squid boxes run CentOS 6.8
> Thanks,
> Walter

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