4 nic ubuntu router

# The loopback network interface
        auto lo
        iface lo inet loopback

#External Interface
        auto eth0
        iface eth0 inet dhcp

#External Interface
        auto eth2
        iface eth2 inet dhcp

#External Interface
        auto eth3
        iface eth3 inet dhcp

#Internal Interface
        auto eth1
        iface eth1 inet static
        address 172.16.32.1
        netmask 255.255.255.0
        network 172.16.32.0
        broadcast 172.16.32.255
                                  

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0.0.0.0         1.1.1.97    0.0.0.0         UG    100    0        0 eth0
1.1.1.96    0.0.0.0         255.255.255.224 U     0      0        0 eth0
1.1.1.96    0.0.0.0         255.255.255.224 U     0      0        0 eth2
1.1.1.96    0.0.0.0         255.255.255.224 U     0      0        0 eth3
172.16.32.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1
                                  

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# delete all existing rules.#
iptables -F
iptables -t nat -F
iptables -t mangle -F
iptables -X



# By default, drop everything except outgoing traffic
#       iptables -P INPUT ACCEPT
#       iptables -P FORWARD ACCEPT
        iptables -P OUTPUT ACCEPT

        echo 1 > /proc/sys/net/ipv4/ip_forward

# Allow established connections, and those not coming from the outside
        iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
        iptables -A INPUT -m state --state NEW -i  eth1 -j ACCEPT
        iptables -A FORWARD -i eth1 -o eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT

# Allow outgoing connections from the LAN side.
        iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT

# Masquerade.
        iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

# Loging
        iptables -A INPUT -j LOG --log-prefix "INPUT_DROP: "
#       iptables -A OUTPUT -j LOG --log-prefix "OUTPUT_DROP: "

# Allow incoming and outgoing for loopback interfaces
        iptables -A INPUT -i lo -j ACCEPT
        iptables -A OUTPUT -o lo -j ACCEPT

# SSH
        iptables -A INPUT -p tcp --dport 22 -m state --state NEW -j ACCEPT

# Ntop
        iptables -A INPUT -p tcp --dport 3000 -m state --state NEW -j DROP

# WebMin
        iptables -A INPUT -p tcp --dport 10000 -m state --state NEW -j DROP



# NAT FORWARDING RULES----------------------------------------------------------
# RDP 3389 to SERVER
        iptables -t nat -A PREROUTING -p tcp -d 1.1.1.1 \
                --dport 3389 -j DNAT --to 172.16.32.50:3389

        iptables -t nat -A POSTROUTING -d 172.16.32.50 -j SNAT \
                --to 172.16.32.1

# RDP 3388 to ALPHA
        iptables -t nat -A PREROUTING -p tcp -d 1.1.1.1 \
                --dport 3388 -j DNAT --to 172.16.32.70:3388

        iptables -t nat -A POSTROUTING -d 172.16.32.70 -j SNAT \
                --to 172.16.32.1

# RDP 3387 to MAGNUS
        iptables -t nat -A PREROUTING -p tcp -d 1.1.1.1 \
                --dport 3387 -j DNAT --to 172.16.32.25:3389

        iptables -t nat -A POSTROUTING -d 172.16.32.25 -j SNAT \
                --to 172.16.32.1

# Squid Forwarding
        iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j REDIRECT --to-port 3128

# Bandwidth Throttling----------------------------------------------------------
# Starts WonderShaper
        wondershaper eth0 5000 5000
                                  

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