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authormbm <mbm@3c298f89-4303-0410-b956-a3cf2f4a3e73>2005-04-23 18:58:32 +0000
committermbm <mbm@3c298f89-4303-0410-b956-a3cf2f4a3e73>2005-04-23 18:58:32 +0000
commit90335cdd41957de7a859232df826cc2bdfc4f3b3 (patch)
tree83e70c4f51e87776cbd7dd30b9f5180fd5136f84 /target/default/target_skeleton/etc
parent59de9d3da5ccfd01e8c17a2844448653bd150036 (diff)
new more flexible firewall
git-svn-id: svn://svn.openwrt.org/openwrt/trunk/openwrt@705 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'target/default/target_skeleton/etc')
-rwxr-xr-xtarget/default/target_skeleton/etc/init.d/S45firewall101
1 files changed, 76 insertions, 25 deletions
diff --git a/target/default/target_skeleton/etc/init.d/S45firewall b/target/default/target_skeleton/etc/init.d/S45firewall
index 51f3a6d1fe..da9fd550f3 100755
--- a/target/default/target_skeleton/etc/init.d/S45firewall
+++ b/target/default/target_skeleton/etc/init.d/S45firewall
@@ -1,36 +1,87 @@
#!/bin/sh
. /etc/functions.sh
-
export WAN=$(nvram get wan_ifname)
-export IPT=/usr/sbin/iptables
+export LAN=$(nvram get lan_ifname)
-for T in filter nat mangle ; do
- $IPT -t $T -F
- $IPT -t $T -X
+## CLEAR TABLES
+for T in filter nat mangle; do
+ iptables -t $T -F
+ iptables -t $T -X
done
-# initial rules
-$IPT -t filter -A INPUT -m state --state INVALID -j DROP
-$IPT -t filter -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-$IPT -t filter -A FORWARD -m state --state INVALID -j DROP
-$IPT -t filter -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
+iptables -N input_rule
+iptables -N output_rule
+iptables -N forwarding_rule
+
+iptables -t nat -N prerouting_rule
+iptables -t nat -N postrouting_rule
+
+### Port forwarding
+# iptables -t nat -A prerouting_rule -p tcp --dport 22 -j DNAT --to 192.168.1.2
+# iptables -A forwarding_rule -p tcp --dport 22 -d 192.168.1.2 -j ACCEPT
+
+### INPUT
+### (connections with the router as destination)
+
+ # base case
+ iptables -P INPUT DROP
+ iptables -A INPUT -m state --state INVALID -j DROP
+ iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
+
+ # allow
+ iptables -A INPUT -i \! $WAN -j ACCEPT # allow from lan/wifi interfaces
+ iptables -A INPUT -p icmp -j ACCEPT # allow ICMP
+ iptables -A INPUT -p 47 -j ACCEPT # allow GRE
+ #
+ # insert accept rule or to jump to new accept-check table here
+ #
+ iptables -A INPUT -j input_rule
+
+ # reject (what to do with anything not allowed earlier)
+ iptables -A INPUT -p tcp --syn --tcp-option \! 2 -j DROP
+ iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset
+ iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable
+
+### OUTPUT
+### (connections with the router as source)
+
+ # base case
+ iptables -P OUTPUT DROP
+ iptables -A OUTPUT -m state --state INVALID -j DROP
+ iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
+
+ # allow
+ iptables -A OUTPUT -j ACCEPT #allow everything out
+ #
+ # insert accept rule or to jump to new accept-check table here
+ #
+ iptables -A OUTPUT -j output_rule
+
+ # reject (what to do with anything not allowed earlier)
+ iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
+ iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
-if [ -d /etc/firewall.d ]; then
- for fw in /etc/firewall.d/??*; do
- [ -x $fw ] && $fw
- done
-fi
+### FORWARDING
+### (connections routed through the router)
-# defaults
+ # base case
+ iptables -P FORWARD DROP
+ iptables -A FORWARD -m state --state INVALID -j DROP
+ iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
+ iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
-$IPT -t filter -A INPUT -p icmp -j ACCEPT
-$IPT -t filter -A INPUT -p 47 -j ACCEPT # allow GRE
-$IPT -t filter -A INPUT -i $WAN -p tcp --syn --tcp-option \! 2 -j DROP
-$IPT -t filter -A INPUT -i $WAN -p tcp -j REJECT --reject-with tcp-reset
-$IPT -t filter -A INPUT -i $WAN -j REJECT --reject-with icmp-port-unreachable
+ # allow
+ iptables -A FORWARD -i br0 -o br0 -j ACCEPT
+ iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
+ #
+ # insert accept rule or to jump to new accept-check table here
+ #
+ iptables -A FORWARD -j forwarding_rule
-$IPT -t filter -A FORWARD -i br0 -o br0 -j ACCEPT
-$IPT -t filter -A FORWARD -i $WAN -m state --state NEW -j DROP
-$IPT -t filter -A FORWARD -o $WAN -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
+ # reject (what to do with anything not allowed earlier)
+ # uses the default -P DROP
-$IPT -t nat -A POSTROUTING -o $WAN -j MASQUERADE
+### MASQ
+ iptables -t nat -A PREROUTING -j prerouting_rule
+ iptables -t nat -A POSTROUTING -j postrouting_rule
+ iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE