Squid proxy with multi wan links and load balancer

hi all
my netowrk interface
eth0 wan1
eht1 wan2
ent2 wan3
eth3 lan 192.168.1.0/24

my iptable T1
wan1 ip dev eth0 scope link
192.168.1.0/24 dev eth3 scope link
default via wan1's dev eth0

iptables -t mangle -A PREROUTING -s 192.168.1.0/24 -j MARK --set-mark 1

http traffic not follow the iptables
sometime via eth1 or eth2

after squid.conf added "tcp_outgoing_address wan1's gateway"
it worked correctly

why??? what squid do???

the http traffic
192.168.1.x http resquset => iptables(nat) redirect 3128 => iptables
(mangle) mark 1
=> route table T1 => internet

why iptables can't not control the traffic

i want creat the tables T2 =>for load balancer
wna1's gateway dev eth0 scope link
wan2's gateway dev eth1 scope link
wan3's gateway dev eth3 scope link
192.168.1.0/24 dev eth3 scope link
default
nexthop via wna1's gateway dev eth0 weight 1 onlink
nexthop via wna2's gateway dev eth1 weight 1 onlink
nexthop via wna3's gateway dev eth2 weight 1 onlink

how to make squid route follow this table

thanks for any advice!!!


##########
I don't think squid could handle the traffic shaping, what I did once was to configure IP route version 2, to have 2 internet providers, and control the access by routing, I wrote all here http://soad1982.blogspot.com/2010/02...-on-linux.html

If you just have one network behind the linux then you can just add the lines at the bottom of the configuration:

ip route add default scope global nexthop via $P1 dev $IF1 weight 1 \
nexthop via $P2 dev $IF2 weight 1


Source: http://www.linuxquestions.org/questions/linux-networking-3/squid-proxy-with-multi-wan-links-and-load-balancer-792457/