On 31.05.2012 05:19, Thomas York wrote:
I've made a LOT of progress with that. The only problem that I'm
having now is making sure that the traffic that is coming from squid
BACK through the same router doesn't get tagged and sent back to the
proxy (causing a loop). I've tried doing different taggings based on
interface, but this doesn’t seem to help at all... I also would have
thought that added a " iptables -t mangle -A PREROUTING -s 10.0.1.1
-j
ACCEPT" to the router would stop this from happening, but it doesn't
look like the traffic from Squid -> Internet web server is using
10.0.1.1, for some reason.
"Some reason" being ... this is "T(ransparent)PROXY", not the hacked up
half-way version of packet interception based on NAT.
Traffic Squid<->Internet has src(client IP):dst(Internet IP) and the
traffic Squid<->client has src(Internet IP):dst(client IP). Squid is
transparent at the IP address level.
That rule will match only the traffic from Squid box generated as a
result of Squid or other software on the box needing to do something
itself (DNS lookups, peer checks, cachemgr operations, etc).
Proxy
------------
ip -f inet rule add fwmark 1 lookup 100
ip -f inet route add local default dev lo table 100
iptables -t mangle -N DIVERT
iptables -t mangle -A DIVERT -j MARK --set-mark 1
iptables -t mangle -A DIVERT -j ACCEPT
iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT
iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY
--tproxy-mark 0x1/0x1 --on-port 3129
root@proxy01:~# ip route list
default via 10.0.1.254 dev eth0
10.0.1.0/24 dev eth0 proto kernel scope link src 10.0.1.1
root@proxy01:~# ip route list table 100
local default dev lo scope host
Router
------------
ip -f inet rule add fwmark 1 lookup 100
ip -f inet route add default via 10.0.1.1 table 100
ip -f inet rule add fwmark 2 lookup 101
ip -f inet route add default via 10.1.17.254 table 101
iptables -t mangle -N DIVERT
iptables -t mangle -A DIVERT -j MARK --set-mark 1
iptables -t mangle -A DIVERT -j ACCEPT
iptables -t mangle -N FROMPROXY
iptables -t mangle -A FROMPROXY -j MARK --set-mark 2
iptables -t mangle -A FROMPROXY -j ACCEPT
iptables -t mangle -A PREROUTING -i eth5 -d 10.0.0.0/8 -j ACCEPT
iptables -t mangle -A PREROUTING -i eth5 -d 192.168.0.0/16 -j ACCEPT
iptables -t mangle -A PREROUTING -i eth5 -j FROMPROXY
iptables -t mangle -A PREROUTING -s 10.0.1.1 -j ACCEPT
iptables -t mangle -A PREROUTING -i eth2 -p tcp --dport 80 -j DIVERT
root@fw:~# ip route list table 100
default via 10.0.1.1 dev eth5
10.0.1.0/24 dev eth5 scope link
root@fw:~# ip route list table 101
default via 10.1.17.254 dev eth0
10.1.17.0/24 dev eth0 scope link
root@fw:~# ip route list
default via 10.1.17.254 dev eth0
10.0.1.0/24 dev eth5 proto kernel scope link src 10.0.1.254
10.1.1.0/24 via 10.100.1.22 dev eth2 metric 110
10.1.17.0/24 dev eth0 proto kernel scope link src 10.1.17.158
AFAIK that should be working.
-- Thomas York
-----Original Message-----
From: Amos Jeffries [mailto:squid3@xxxxxxxxxxxxx]
Sent: Tuesday, May 29, 2012 8:00 PM
To: squid-users@xxxxxxxxxxxxxxx
Subject: RE: Linux + TPROXY + Remote Squid
On 30.05.2012 01:49, Thomas York wrote:
Is any more information needed?
-- Thomas York
-----Original Message-----
From: Thomas York
Sent: Friday, May 25, 2012 1:37 PM
I forgot one detail. I have an iptables rule BEFORE the PREROUTING
divert/tproxy iptables rules on the router. I added an accept so
that
HTTP traffic from the proxy doesn't get tagged and rerouted to the
proxy.
Here's the rule set I have for the firewall
iptables -t mangle -N DIVERT
iptables -t mangle -A DIVERT -j MARK --set-mark 1 iptables -t mangle
-A DIVERT -j ACCEPT iptables -t mangle -A PREROUTING -s 10.0.1.1 -j
ACCEPT iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT
iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY
--tproxy-mark
0x1/0x1 --on-port 3129
With Squid listening on localhost port 3129 to receive the packets
sent to 0.0.0.0:3129 and [::]:3129 ?
When the router is a different box to the Squid you should do all
this with plain old routing and marking/tagging (no TPROXY) on the
router.
-----Original Message-----
From: Thomas York
Sent: Friday, May 25, 2012 1:32 PM
No. The router has three interfaces. One goes to the internet and
has
a
default route. I am running NAT on this interface so that the
firewall,
proxy
and clients can reach the internet. The second is a single /24
network
(10.0.1.0/24) that has only the proxy and the firewall on it. The
third is a
single /24 (10.1.1.0/24) that has a single Windows 7 client on it
for
generating HTTP requests and testing. I'm tagging the packets on
the
firewall
and running them through a separate routing table, which sends the
packets
to
the proxy (without NAT-ing). The proxy and the firewall see the
routed
packets
perfectly fine. I'm not doing any kind of iptables rules on the
proxy,
however.
This is the problem. TPROXY rules are iptables rules supposed to be
on
the proxy machine *only*. Outside that proxy box all packets have
client
and Internet destination IP addresses and get routed.
NIC flow in/out or MAC address is best to identify which stage of the
flow the packets are at and how to tag/handle them in the routers. It
may require several tags at the router; for packets direct from
client
or Internet, and packets already been via Squid/proxy box.
OR just routing based on NIC received...
ie, Router config logic:
if in NIC (from client) tag for routing and send to Squid box as
gateway
if in NIC (from Internet) tag for routing and send to Squid box as
gateway
if in NIC (from Squid) handle as if Squid did not exist: send to
normal IP destination on packet
Amos
