如何配置 ufw 或 iptables 以仅允许从 IPv6 网络到 Internet 的出站流量？
我有一个办公室网络，其中采用传统的 IPv4 NAT 设置。我想添加一台运行 Ubuntu 的 PC，利用 Hurricane Electric 的隧道充当 IPv6 路由器。
我已设置好一切，一切运行正常。我的内部计算机正在从 Ubuntu 盒子接收全局地址，并且能够 ping ipv6.google.com 并浏览 ipv6test.google.com，没有任何问题。
我不确定的是如何配置防火墙来阻止从互联网到我的内部网络的未经请求的流量，但允许到互联网的出站流量（以及相关的返回流量）。
如能提供 ufw 命令或 iptables 规则的实际示例，我们将不胜感激。
root@ipv6router:/home/corey# ifconfig
eth0 Link encap:Ethernet HWaddr 00:08:a1:10:62:c0
inet addr:146.x.y.12 Bcast:146.x.y.15 Mask:255.255.255.240
inet6 addr: fe80::208:a1ff:fe10:62c0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:190487 errors:1 dropped:0 overruns:1 frame:1
TX packets:40982 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:80088076 (80.0 MB) TX bytes:6825762 (6.8 MB)
eth1 Link encap:Ethernet HWaddr 00:1b:21:5b:f0:5b
inet addr:192.168.76.3 Bcast:192.168.76.255 Mask:255.255.255.0
inet6 addr: fe80::21b:21ff:fe5b:f05b/64 Scope:Link
inet6 addr: 2001:x:1f07:z::1/64 Scope:Global
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:90200 errors:0 dropped:0 overruns:0 frame:0
TX packets:59894 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:12839775 (12.8 MB) TX bytes:70668474 (70.6 MB)
he-ipv6 Link encap:IPv6-in-IPv4
inet6 addr: fe80::9273:130c/128 Scope:Link
inet6 addr: 2001:x:1f06:z::2/64 Scope:Global
UP POINTOPOINT RUNNING NOARP MTU:1480 Metric:1
RX packets:56991 errors:0 dropped:0 overruns:0 frame:0
TX packets:34362 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:69388394 (69.3 MB) TX bytes:4537403 (4.5 MB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:13137 errors:0 dropped:0 overruns:0 frame:0
TX packets:13137 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:998616 (998.6 KB) TX bytes:998616 (998.6 KB)
root@ipv6router:/home/corey# route -A inet6
Kernel IPv6 routing table
Destination Next Hop Flag Met Ref Use If
2001:x:1f06:z::1/128 :: U 1024 0 1 he-ipv6
2001:x:1f06:z::/64 :: Un 256 0 0 he-ipv6
2001:x:1f07:z::/64 :: U 256 0 0 eth1
fe80::/64 :: U 256 0 0 eth1
fe80::/64 :: Un 256 0 0 he-ipv6
fe80::/64 :: U 256 0 0 eth0
::/0 2001:x:1f06:z::1 UG 1024 0 0 he-ipv6
::/0 :: !n -1 1 92337 lo
::1/128 :: Un 0 1 412 lo
2001:x:1f06:z::/128 :: Un 0 1 0 lo
2001:x:1f06:z::2/128 :: Un 0 1 736 lo
2001:x:1f07:z::/128 :: Un 0 1 0 lo
2001:x:1f07:z::1/128 :: Un 0 1 0 lo
fe80::/128 :: Un 0 1 0 lo
fe80::/128 :: Un 0 1 0 lo
fe80::9273:130c/128 :: Un 0 1 0 lo
fe80::208:a1ff:fe10:62c0/128 :: Un 0 1 0 lo
fe80::21b:21ff:fe5b:f05b/128 :: Un 0 1 4611 lo
ff00::/8 :: U 256 0 0 eth1
ff00::/8 :: U 256 0 0 he-ipv6
ff00::/8 :: U 256 0 0 eth0
::/0 :: !n -1 1 92337 lo
答案1
使用forward链添加转发防火墙规则。
ip6tables -A FORWARD -i he-ipv6 -m state --state ESTABLISHED,RELATED -j ACCEPT # Accept already established connections (return traffic, for instance)
ip6tables -A FORWARD -i he-ipv6 -j DROP # Drop the rest
ip6tables -A FORWARD -o he-ipv6 -j ACCEPT # Accept outbound connections to the ipv6 tunnel
ip6tables -P FORWARD DROP # Set default policy on forward chain
通过此设置，您将需要添加更多规则以让其他接口按您希望的方式路由，但最终结果与上面的非常相似。