Allow access from outside network with dmz and iptables

Question

I'm having a problem with my home network. So my setup is like this:

In my Router (using Ubuntu desktop v11.04), I installed squid proxy as my transparent proxy.

So I would like to use dyndns to my home network so I could be access my server from the internet, and also I installed CCTV camera and I would like to enable watching it from internet.

The problem is I cannot access it from outside the net.
I already set DMZ in my modem to my router ip.

My first guess is because i'm using iptables to redirect all inside network to use squid.
And not allow from outside traffic to my inside network.
Here is my iptables script:

#!/bin/sh

# squid server IP
SQUID_SERVER="192.168.5.1"

# Interface connected to Internet
INTERNET="eth0"

# Interface connected to LAN
LAN_IN="eth1"

# Squid port
SQUID_PORT="3128"

# Clean old firewall
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
# Load IPTABLES modules for NAT and IP conntrack support
modprobe ip_conntrack
modprobe ip_conntrack_ftp
# For win xp ftp client
#modprobe ip_nat_ftp
echo 1 > /proc/sys/net/ipv4/ip_forward
# Setting default filter policy
iptables -P INPUT DROP
iptables -P OUTPUT ACCEPT
# Unlimited access to loop back
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
# Allow UDP, DNS and Passive FTP
iptables -A INPUT -i $INTERNET -m state --state ESTABLISHED,RELATED -j ACCEPT
# set this system as a router for Rest of LAN
iptables --table nat --append POSTROUTING --out-interface $INTERNET -j MASQUERADE
iptables --append FORWARD --in-interface $LAN_IN -j ACCEPT
# unlimited access to LAN
iptables -A INPUT -i $LAN_IN -j ACCEPT
iptables -A OUTPUT -o $LAN_IN -j ACCEPT
# DNAT port 80 request comming from LAN systems to squid 3128 ($SQUID_PORT) aka     transparent proxy
iptables -t nat -A PREROUTING -i $LAN_IN -p tcp --dport 80 -j DNAT --to     $SQUID_SERVER:$SQUID_PORT
# if it is same system
iptables -t nat -A PREROUTING -i $INTERNET -p tcp --dport 80 -j REDIRECT --to-port     $SQUID_PORT
# DROP everything and Log it
iptables -A INPUT -j LOG
iptables -A INPUT -j DROP

If you know where did I miss, please advice me.
Thanks for all your help and I really appreciate it.

Answer 1

Just an opinion, but it seems to me that you're only forwarding port 80 connection to SQUID:
iptables -t nat -A PREROUTING -i $LAN_IN -p tcp --dport 80 -j DNAT --to $SQUID_SERVER:$SQUID_PORT

Shouldn't all packets be forwarded over to SQUID (especially DNS , and the port used by the camera)?