On 6/02/2013 11:43 a.m., Marcel Steinbach wrote:
Hi,
I want to setup an interception proxy with DNAT using squid 3.2.7.
My squid.conf is
acl trusted src x.x.x.x y.y.y.y
acl SSL_ports port 443
acl Safe_ports port 80 # http
acl Safe_ports port 21 # ftp
acl Safe_ports port 443 # https
acl Safe_ports port 70 # gopher
acl Safe_ports port 210 # wais
acl Safe_ports port 1025-65535 # unregistered ports
acl Safe_ports port 280 # http-mgmt
acl Safe_ports port 488 # gss-http
acl Safe_ports port 591 # filemaker
acl Safe_ports port 777 # multiling http
acl CONNECT method CONNECT
http_access allow manager localhost
http_access deny manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow trusted
http_access allow localhost
http_access deny all
http_port 0.0.0.0:8888
http_port 0.0.0.0:8128 intercept
hierarchy_stoplist cgi-bin ?
NP: hierarchy_stoplist is not useful for general use anymore. You should
remove this line unless you actually need it.
debug_options ALL,1
coredump_dir /var/spool/squid3
cache deny all
refresh_pattern ^ftp: 1440 20% 10080
refresh_pattern ^gopher: 1440 0% 1440
refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
refresh_pattern . 0 20% 4320
request_header_access Proxy-Connection deny all
request_header_access X-Forwarded-For deny all
NP: in 3.2 this hack is no longer needed.
Use "forwarded_for delete" to strip XFF headers instead.
Use "forwarded_for transparent" to pass external softwares XFF headers
without adding one for this proxy.
request_header_access Connection deny all
request_header_access Via deny all
forwarded_for off
I've set up the iptables and sysctl.conf as described in http://wiki.squid-cache.org/ConfigExamples/Intercept/LinuxDnat
$ iptables -t nat --list-rules
-P PREROUTING ACCEPT
-P POSTROUTING ACCEPT
-P OUTPUT ACCEPT
-A PREROUTING -s 209.141.35.219/32 -p tcp -m tcp --dport 80 -j ACCEPT
-A PREROUTING -p tcp -m tcp --dport 80 -j DNAT --to-destination 209.141.35.219:8128
-A POSTROUTING -j MASQUERADE
$ iptables -t mangle --list-rules
-P PREROUTING ACCEPT
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-P POSTROUTING ACCEPT
-A PREROUTING -p tcp -m tcp --dport 8128 -j DROP
These rules look fine *if* they are on the Squid box itself. DNAT _must
not_ be configured on an external box.
In my client network, I've set up a dnsmasq to redirect the hosts that I want to proxy to the squid box.
However, when I call one of the hosts, e.g. www.example.org, I get
ERROR
The requested URL could not be retrieved
The following error was encountered while trying to retrieve the URL: http://example.org/
Connection to <squid-ip> failed.
The system returned: (111) Connection refused
Because dnsmasq has told the client (and Squid) that the origin server
hosting this domain is the Squid box.
There is no web server running on the Squid box port 80.
Why are you using dnsmasq instead of policy routing?
Amos
