[squid-users] Parent proxy chaining

[Matus UHLAR - fantomas]

On 27.11.18 08:33, Phillip McCollum wrote:
>I have a deployment in AWS in where a VPC has a transparent proxy deployed,
>which forwards 80/443 requests to a parent proxy in another VPC, which I
>then need to forward to another parent proxy (SaaS provider).
>
>Essentially:
>[[Client PC]] --> [[Squid Proxy (10.52.0.20)]] --> [[Parent Squid Proxy
>(10.52.0.168)]] --> [[Parent SaaS Proxy]]
>
>This is being done to centralize proxy functions and limit the number of
>public IPs that the parent SaaS needs to whitelist.
>
>I'm getting "Access Denied" messages and a review of Squid Parent proxy
>access.log shows the following common errors:
>
>HTTP:
>2018/11/27 16:22:54 kid1| WARNING: Forwarding loop detected for:
>GET / HTTP/1.1
>Accept: text/html, application/xhtml+xml, image/jxr, */*
>Accept-Language: en-US
>User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like
>Gecko
>Accept-Encoding: gzip, deflate
>Cookie: B=8nra62ldvb83a&b=3&s=ik
>Via: 1.1 squid (squid/3.5.27)

what are names of your proxies?
you must set different visible_name or at least unique_name so proxy knows
it's not contacting itself.

>Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
> pkts bytes target     prot opt in     out     source
> destination
>    0     0 REDIRECT   tcp  --  *      *       0.0.0.0/0
>0.0.0.0/0            tcp dpt:80 redir ports 3129
>    0     0 REDIRECT   tcp  --  *      *       0.0.0.0/0
>0.0.0.0/0            tcp dpt:443 redir ports 3130
>   35  2100 REDIRECT   tcp  --  *      *       0.0.0.0/0
>0.0.0.0/0            tcp dpt:8443 redir ports 3031

the intercepting (often called transparent) proxy must have direct access to
world or parent proxy. Redirecting it back will create a loop.


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