114 lines
4.1 KiB
Bash
114 lines
4.1 KiB
Bash
#!/bin/bash
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# Enable debugging, makes it easier to detect faulty commands
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set -x
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### Clear all old rules
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iptables -P INPUT ACCEPT
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iptables -P OUTPUT ACCEPT
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iptables -P FORWARD ACCEPT
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ip6tables -P INPUT ACCEPT
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ip6tables -P OUTPUT ACCEPT
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ip6tables -P FORWARD ACCEPT
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iptables -F
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iptables -X
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iptables -t nat -F
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iptables -t nat -X
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ip6tables -F
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ip6tables -X
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# Exit in case you only want to clear all existing rules
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#exit 0;
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### New rules start here
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# Default policy ist DROP.
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iptables -P INPUT DROP
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iptables -P OUTPUT DROP
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iptables -P FORWARD DROP
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ip6tables -P INPUT DROP
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ip6tables -P OUTPUT DROP
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ip6tables -P FORWARD DROP
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# Install a chain for logging and dropping traffic
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# This helps with debugging a bit
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iptables -N log_and_drop
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iptables -A log_and_drop -j LOG --log-level debug --log-prefix " "
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iptables -A log_and_drop -j DROP
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ip6tables -N log_and_drop
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ip6tables -A log_and_drop -j LOG --log-level debug --log-prefix " "
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ip6tables -A log_and_drop -j DROP
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# Datenverkehr über Loopback-Interface ist immer erlaubt.
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iptables -A INPUT -i lo -j ACCEPT
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iptables -A OUTPUT -o lo -j ACCEPT
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ip6tables -A INPUT -i lo -j ACCEPT
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ip6tables -A OUTPUT -o lo -j ACCEPT
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# Die Protokolle ICMP und ICPMv6 sind immer erlaubt.
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iptables -A INPUT -p icmp -j ACCEPT
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iptables -A OUTPUT -p icmp -j ACCEPT
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iptables -A FORWARD -p icmp -j ACCEPT
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ip6tables -A INPUT -p icmpv6 -j ACCEPT
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ip6tables -A OUTPUT -p icmpv6 -j ACCEPT
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ip6tables -A FORWARD -p icmpv6 -j ACCEPT
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# Zugriffe auf den VPN-Server sind für Dienste SSH und OpenVPN erlaubt.
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iptables -A INPUT -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
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ip6tables -A INPUT -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
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iptables -A INPUT -p udp --dport 1194 -j ACCEPT
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ip6tables -A INPUT -p udp --dport 1194 -j ACCEPT
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# Antwortpakete auf eingehende Pakete für SSH und OpenVPN sind erlaubt.
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iptables -A OUTPUT -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
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ip6tables -A OUTPUT -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
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iptables -A OUTPUT -p udp --sport 1194 -j ACCEPT
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ip6tables -A OUTPUT -p udp --sport 1194 -j ACCEPT
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# Vom VPN-Server ausgehende Pakete sind grundsätzlich erlaubt.
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iptables -A OUTPUT -m state --state NEW,ESTABLISHED -j ACCEPT
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ip6tables -A OUTPUT -m state --state NEW,ESTABLISHED -j ACCEPT
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# Zum VPN-Server eingehende Pakete sind als Antwort auf ausgehende Pakete erlaubt.
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iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
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ip6tables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
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# Für IPv4-Verkehr aus dem VPN in andere Netze soll NAT mit Absender-IP 141.71.38.7 durchgeführt werden.
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iptables -t nat -A POSTROUTING -s 10.2.0.0/16 ! -d 10.2.0.0/16 -j SNAT --to 141.71.38.7
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# Datenverkehr zwischen VPN-Clients ist verboten und wird verworfen.
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iptables -A FORWARD -s 10.2.0.0/16 -d 10.2.0.0/16 -j log_and_drop
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ip6tables -A FORWARD -s 2001:638:614:1750::/64 -d 2001:638:614:1750::/64 -j log_and_drop
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# Datenverkehr aus dem VPN zu NFS (Port 2049) ist verboten.
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iptables -A FORWARD -s 10.2.0.0/16 -p tcp --dport 2049 -j log_and_drop
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iptables -A FORWARD -s 10.2.0.0/16 -p udp --dport 2049 -j log_and_drop
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ip6tables -A FORWARD -s 2001:638:614:1750::/64 -p tcp --dport 2049 -j log_and_drop
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ip6tables -A FORWARD -s 2001:638:614:1750::/64 -p udp --dport 2049 -j log_and_drop
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# Jeglicher weiterer Datenverkehr aus dem VPN ist erlaubt.
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iptables -A FORWARD -s 10.2.0.0/16 -m state --state NEW,ESTABLISHED -j ACCEPT
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ip6tables -A FORWARD -s 2001:638:614:1750::/64 -m state --state NEW,ESTABLISHED -j ACCEPT
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# In das VPN eingehender Verkehr ist nur als Antwort auf ausgehende Pakete erlaubt.
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iptables -A FORWARD -d 10.2.0.0/16 -m state --state ESTABLISHED,RELATED -j ACCEPT
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ip6tables -A FORWARD -d 2001:638:614:1750::/64 -m state --state ESTABLISHED,RELATED -j ACCEPT
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# Log everything else that is supposed to get dropped by default
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iptables -A INPUT -j log_and_drop
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iptables -A OUTPUT -j log_and_drop
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iptables -A FORWARD -j log_and_drop
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ip6tables -A INPUT -j log_and_drop
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ip6tables -A OUTPUT -j log_and_drop
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ip6tables -A FORWARD -j log_and_drop
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### Save the new rules to disk
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iptables-save > /etc/iptables/rules.v4
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ip6tables-save > /etc/iptables/rules.v6
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