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## 1.b
######

# drop ALL input and output connections. Note that this also drops loopback connections
sudo iptables -P INPUT DROP
# sudo iptables -P OUTPUT DROP

# accept incoming and outgoing connections on loopback to allow ping to work
# Neccessary to provide full functionality to most services
# sudo iptables -A INPUT -i lo -j ACCEPT
# sudo iptables -A OUTPUT -o lo -j ACCEPT

# accept incoming connections on the SSH port of 22
sudo iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
# accept incoming connections on the HTTP port of 80
sudo iptables -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT

# in order to get SSH service working correctly the following output connections would need to be allowed on state ESTABLISHED
# sudo iptables -A OUTPUT -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
# in order to get HTTP service working correctly the following output connections would need to be allowed on state ESTABLISHED
# sudo iptables -A OUTPUT -p tcp --sport 80 -m conntrack --ctstate ESTABLISHED -j ACCEPT

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## 1.c
######

# create a new iptable chain called LOGGING
iptables -N LOGGING

# direct all remaining incomming packets to the LOGGING chain
iptables -A INPUT -j LOGGING

# create the log, on the LOGGING chain, with prefix, and logging level 4 (warning)
# logs are written to /var/log/messages
iptables -A LOGGING -j LOG --log-prefix "IPTABLES mark" --log-level 4

# drop all remaining packets still in chain
# iptables -A LOGGING -j DROP

######
## 1.d
######

iptables -A LOGGING -p tcp --tcp-flag ALL SYN -m limit --limit 10/m -j LOG --log-prefix "IPTABLES PORTSCAN mark" --log-level 4

# drop all remaining packets still in chain
iptables -A LOGGING -j DROP

# iptables -A INPUT -p tcp -i eth1 -m state --state NEW -m recent --set
# iptables -A INPUT -p tcp -i eth1 -m state --state NEW -m recent --update --seconds 30 --hitcount 10 -j LOG --log-prefix " " --log-level 4

# iptables -A FORWARD -p tcp -i eth1 -m state --state NEW -m recent --set
# iptables -A FORWARD -p tcp -i eth1 -m state --state NEW -m recent --update --seconds 30 --hitcount 10 -j LOG --log-prefix "IPTABLES portscan mark " --log-level 4