Re: [squid-users] TPROXY Interception and Multiples ISP Rules (Shorewall) dont work

On 09/05/2012 03:19, Amos Jeffries wrote:
> On 09.05.2012 03:07, Vinicius R. Baenas wrote:
>> Hello,
>>
>> I wonder if someone could use the TPROXY with Shorewall and
>> transparent Squid with using the routing rules on shorewall (tcrules)
>> for hosts / networks (LAN) with multiples providers (WANs) directly
>> from the internal network on port 80 (with TPROXY transparent squid or
>> REDIRECT).
>> On this issue, the routing rules is not work propertly because the
>> source is the firewall ($FW) not the hosts or networks (LAN).
>> My guess is the TPRoxy interception (spoofing) is not working...
>> Thank you...
>
>
> REDIRECT uses NAT which erases the IP addresses and would always lead to
> the behaviour you describe.
>
> TPROXY would only result in such behaviour if not working. But you don't
> say what software versions you have on the box running Squid. TPROXY is
> new enough that specific minimum versions are still very important and
> bugs exist in uncommon use-cases. wiki.squid-cache.org/Features/Tproxy4
> covers the specifics.
>
> Amos
>
i was curios about it and found out that Shorewall is using iptables
mark to loadbalance and direct\route traffic in a multi-wan setup so
it's pretty obvious why this accrues for tproxy.
if it uses some prerouting mangle to mark the packets,
then they are remarked for tproxy and the whole multi-wan setup\settings
is useless.
that is why it's better used on a routing level while using tproxy.

Eliezer

-- 
Eliezer Croitoru
https://www1.ngtech.co.il
IT consulting for Nonprofit organizations
eliezer <at> ngtech.co.il