3 ## Please make changes in /etc/firewall.user
7 . /etc/network.overrides
8 [ "$FAILSAFE" != "true" -a -e /etc/config/network ] && . /etc/config/network
10 WAN=$(nvram get wan_ifname)
11 LAN=$(nvram get lan_ifname)
14 for T in filter nat; do
19 iptables -N input_rule
20 iptables -N output_rule
21 iptables -N forwarding_rule
23 iptables -t nat -N prerouting_rule
24 iptables -t nat -N postrouting_rule
27 ### (connections with the router as destination)
30 iptables -P INPUT DROP
31 iptables -A INPUT -m state --state INVALID -j DROP
32 iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
33 iptables -A INPUT -p tcp --tcp-flags SYN SYN --tcp-option \! 2 -j DROP
36 # insert accept rule or to jump to new accept-check table here
38 iptables -A INPUT -j input_rule
41 iptables -A INPUT ${WAN:+-i \! $WAN} -j ACCEPT # allow from lan/wifi interfaces
42 iptables -A INPUT -p icmp -j ACCEPT # allow ICMP
43 iptables -A INPUT -p gre -j ACCEPT # allow GRE
45 # reject (what to do with anything not allowed earlier)
46 iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset
47 iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable
50 ### (connections with the router as source)
53 iptables -P OUTPUT DROP
54 iptables -A OUTPUT -m state --state INVALID -j DROP
55 iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
58 # insert accept rule or to jump to new accept-check table here
60 iptables -A OUTPUT -j output_rule
63 iptables -A OUTPUT -j ACCEPT #allow everything out
65 # reject (what to do with anything not allowed earlier)
66 iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
67 iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
70 ### (connections routed through the router)
73 iptables -P FORWARD DROP
74 iptables -A FORWARD -m state --state INVALID -j DROP
75 iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
76 iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
79 # insert accept rule or to jump to new accept-check table here
81 iptables -A FORWARD -j forwarding_rule
84 # if there is bridge splitting this workaround works too
86 iptables -A FORWARD -i $iface -o $iface -j ACCEPT
87 [ -z "$WAN" ] || iptables -A FORWARD -i $iface -o $WAN -j ACCEPT
89 # reject (what to do with anything not allowed earlier)
90 # uses the default -P DROP
93 iptables -t nat -A PREROUTING -j prerouting_rule
94 iptables -t nat -A POSTROUTING -j postrouting_rule
95 [ -z "$WAN" ] || iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE
98 [ -f /etc/firewall.user ] && . /etc/firewall.user