Upgrading firewall

[jserrachinha <jserrachinha@camilopinto.pt>]

Hi,

I'm using 3 boxs of debian sid. One is the firewall. I'm using squid. I 
have this rule:
iptables -t nat -A PREROUTING -p TCP --dport 80 -j REDIRECT --to-port 3128

Since this rule is for ethx traffic, how can i put apt-get using the squid?
The problem is the firewall box, the others are working fine with squid.

Thanks in advance.