> Попробовала так, не получается...
> iptables -t nat -A PREROUTING -i $LAN,$LAN2,$LAN3 -p tcp --dport $HTTP  
> -j REDIRECT --to-port $SQUIDH
> iptables -t nat -A PREROUTING -i $LAN,$LAN2,$LAN3 -p tcp --dport $HTTPS -j
> REDIRECT --to-port $SQUIDS
> Спасибо!!!

for iface in $LAN $LAN2 $LAN3; do
    iptables -t nat -A PREROUTING -i ${iface} -p tcp --dport $HTTP -j REDIRECT --to-port $SQUID
    iptables -t nat -A PREROUTING -i ${iface} -p tcp --dport $HTTPS -j REDIRECT --to-port $SQUIDS
done