139 lines
4.9 KiB
Bash
Executable file
139 lines
4.9 KiB
Bash
Executable file
#!/bin/bash
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# The name of the main external interface.
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EX_IF="br0"
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# The IP ranges from where to accept unfiltered connections.
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UNFILTERED_RANGES_V4=('212.78.94.73' '216.119.155.58-216.119.155.62' '91.109.244.7-91.109.244.11' '185.176.90.169')
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UNFILTERED_RANGES_V6=('2a02:2498:e004:2a::/64' '2a02:2498:1:227::/64' '2a07:4580:b0d:57f::/64')
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start_firewall() {
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# Disable ICMP redirects.
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# Note: Redirects are used when a router believes a packet is being routed sub optimally and it would like to inform
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# the sending host that it should forward subsequent packets to that same destination through a different gateway.
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echo 0 >"/proc/sys/net/ipv4/conf/$EX_IF/accept_redirects"
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echo 0 >"/proc/sys/net/ipv6/conf/$EX_IF/accept_redirects"
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echo 0 >"/proc/sys/net/ipv4/conf/$EX_IF/send_redirects"
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# Flush old rules.
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iptables -F
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ip6tables -F
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iptables -t nat -F
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ip6tables -t nat -F
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iptables -t mangle -F
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ip6tables -t mangle -F
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# Delete any custom chains.
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iptables -X
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ip6tables -X
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iptables -t nat -X
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ip6tables -t nat -X
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iptables -t mangle -X
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ip6tables -t mangle -X
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# Drop invalid packets on all interfaces.
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iptables -A INPUT -m conntrack --ctstate INVALID -j DROP
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ip6tables -A INPUT -m conntrack --ctstate INVALID -j DROP
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# Drop unroutable IPs on the external interface.
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iptables -A INPUT -i "$EX_IF" -s 127.0.0.0/8 -j DROP
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ip6tables -A INPUT -i "$EX_IF" -s ::1/128 -j DROP
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iptables -A INPUT -i "$EX_IF" -s 10.0.0.0/8 -j DROP
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iptables -A INPUT -i "$EX_IF" -s 172.16.0.0/12 -j DROP
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iptables -A INPUT -i "$EX_IF" -s 192.168.0.0/16 -j DROP
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# Allow all loopback traffic.
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iptables -A INPUT -i lo -j ACCEPT
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ip6tables -A INPUT -i lo -j ACCEPT
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# Allow unrestricted access from our IPs.
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for IPRANGE in "${UNFILTERED_RANGES_V4[@]}"; do
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iptables -A INPUT -i "$EX_IF" -m iprange --src-range "$IPRANGE" -j ACCEPT
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done
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for IPRANGE in "${UNFILTERED_RANGES_V6[@]}"; do
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ip6tables -A INPUT -i "$EX_IF" -s "$IPRANGE" -j ACCEPT
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done
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# Allow packets of established connections and those related to them.
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iptables -A INPUT -i "$EX_IF" -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
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# Allow pings.
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iptables -A INPUT -i "$EX_IF" -p icmp -m icmp --icmp-type echo-request -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p icmpv6 --icmpv6-type echo-request -j ACCEPT
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iptables -A INPUT -i "$EX_IF" -p icmp --icmp-type echo-reply -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p icmpv6 --icmpv6-type echo-reply -j ACCEPT
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# Allow certain types of ICMP informational packets.
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iptables -A INPUT -i "$EX_IF" -p icmp --icmp-type destination-unreachable -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p icmpv6 --icmpv6-type destination-unreachable -j ACCEPT
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iptables -A INPUT -i "$EX_IF" -p icmp --icmp-type time-exceeded -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p icmpv6 --icmpv6-type time-exceeded -j ACCEPT
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iptables -A INPUT -i "$EX_IF" -p icmp --icmp-type parameter-problem -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p icmpv6 --icmpv6-type parameter-problem -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p icmpv6 --icmpv6-type packet-too-big -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p icmpv6 --icmpv6-type neighbour-solicitation -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p icmpv6 --icmpv6-type neighbour-advertisement -j ACCEPT
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# Allow SSH.
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iptables -A INPUT -i "$EX_IF" -p tcp --syn -m multiport --dports 22,9922 -m conntrack --ctstate NEW -j ACCEPT
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ip6tables -A INPUT -i "$EX_IF" -p tcp --syn -m multiport --dports 22,9922 -m conntrack --ctstate NEW -j ACCEPT
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# Set default policies.
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iptables -P INPUT DROP
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ip6tables -P INPUT DROP
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iptables -P OUTPUT ACCEPT # We don't firewall outgoing connections.
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ip6tables -P OUTPUT ACCEPT # We don't firewall outgoing connections.
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iptables -P FORWARD DROP
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ip6tables -P FORWARD DROP
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}
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stop_firewall() {
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# Set default policies to ACCEPT.
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iptables -P INPUT ACCEPT
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ip6tables -P INPUT ACCEPT
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iptables -P OUTPUT ACCEPT
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ip6tables -P OUTPUT ACCEPT
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iptables -P FORWARD ACCEPT
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ip6tables -P FORWARD ACCEPT
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# Flush rules.
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iptables -F
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ip6tables -F
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iptables -t nat -F
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ip6tables -t nat -F
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iptables -t mangle -F
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ip6tables -t mangle -F
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# Delete any custom chains.
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iptables -X
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ip6tables -X
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iptables -t nat -X
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ip6tables -t nat -X
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iptables -t mangle -X
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ip6tables -t mangle -X
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# Reset ICMP redirects.
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cat /proc/sys/net/ipv4/conf/default/accept_redirects >"/proc/sys/net/ipv4/conf/$EX_IF/accept_redirects"
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cat /proc/sys/net/ipv6/conf/default/accept_redirects >"/proc/sys/net/ipv6/conf/$EX_IF/accept_redirects"
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cat /proc/sys/net/ipv4/conf/default/send_redirects >"/proc/sys/net/ipv4/conf/$EX_IF/send_redirects"
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}
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case "$1" in
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'start')
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start_firewall
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;;
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'stop')
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stop_firewall
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;;
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'restart')
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stop_firewall
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start_firewall
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;;
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*)
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echo "Usage: $BASH_SOURCE <start|stop|restart>" >&2
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ERR=1
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;;
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esac
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