# NOTES 1

sudo apt-get install iptables-persistent

sudo iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT -m state --state RELATED,ESTABLISHED
sudo iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

# uncomment #net.ipv4.ip_forward=1
sudo nano /etc/sysctl.conf
sudo sysctl -p /etc/sysctl.conf
sudo service iptables-persistent save

sudo iptables -I FORWARD -p tcp -i eth0 -d 10.0.10.130 --dport 80 -j ACCEPT
sudo iptables -I FORWARD -p tcp -i eth0 -d 10.0.10.130 --dport 3389 -j ACCEPT
sudo iptables -t nat -A PREROUTING -p tcp -i eth0 -d 10.0.10.130 --dport 80 -j DNAT --to-destination 10.0.13.3:80
sudo iptables -t nat -A PREROUTING -p tcp -i eth0 -d 10.0.10.130 --dport 3389 -j DNAT --to-destination 10.0.13.3:3389

sudo iptables -L
sudo iptables -t nat -L


# NOTES 2 (WORKING)

# Setup and install

sudo apt-get install iptables-persistent
# uncomment #net.ipv4.ip_forward=1
sudo nano /etc/sysctl.conf
sudo sysctl -p /etc/sysctl.conf
sudo service iptables-persistent save


# NAT Across CIDR blocks except for 10.0.10.0/24 and 10.0.11.0/24 (= 10.0.10.0/23). 10.0.0.0/8 is ignored below.

sudo iptables -t nat -A POSTROUTING -o eth0 -d 0.0.0.0/5 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -o eth0 -d 8.0.0.0/7 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -o eth0 -d 11.0.0.0/8 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -o eth0 -d 12.0.0.0/6 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -o eth0 -d 16.0.0.0/4 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -o eth0 -d 32.0.0.0/3 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -o eth0 -d 64.0.0.0/2 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -o eth0 -d 128.0.0.0/1 -j MASQUERADE

# Fix windows firewall to accept the appropriate ports. For testing, you can turn off windows firewall and ping across.

# Install DNS
sudo apt-get update
sudo apt-get install bind9 bind9utils bind9-doc

sudo service iptables-persistent save

# RDP from 10.0.10.104 into 10.0.10.130 which converts to 10.0.13.2
sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 3389 -j DNAT --to 10.0.13.2:3389

sudo iptables -t nat -L -n --line-numbers
sudo iptables —t nat -D PREROUTING 1