Security gateway and 6bone connection

Jun-ichiro itojun Hagino (Itoh), KAME Project
$Id: index.html,v 1.1 2001/04/17 03:42:20 itojun Exp $

Recently we got several emails about how you can hook your site up to 6bone, when you have security gateway (packet filters) on your IPv4 router.

The configuration for Checkpoint Firewall-1 is provided by Mr. Tetsuhiro Nakane. Thanks!


Most of 6bone connetion is done by RFC1933 IPv6-to-IPv4 tunnel. The packet will look like this:
15:49:28.631199 > 2010:836b:4179:2:260:8ff:febf:b622 > 3ffe:501:410:0:240:5ff:fea0:8e08: icmp6: echo request (encap)
                         4500 0064 f5bf 0000 1329 2b3f cbb2 88bc
                         d2a0 5f63 6000 0000 0028 3af6 2010 836b
                         4179 0002 0260 08ff febf b622 3ffe 0501
                         0410 0000 0240 05ff fea0 8e08 8000 a7d3
                         001e a9d7 6162 6364 6566 6768 696a 6b6c
                         6d6e 6f70 7172 7374 7576 7761 6263 6465
                         6667 6869
All you need to do is to let the packet go through the firewall gateway. The packet has IPv4 protocol number field (ip->ip_p) of 41 (0x29), which is marked with red color on the above packet dump. You may also want to restrict IPv4 source address and destination address, to make sure that no malicious IPv6 tunnels can be established.

Configuring Checkpoint Firewall-1

Suppose you have Checkpoint Firewall-1 (FW-1) between your tunnel endpoint (A) and the peer (B).
A ==== FW-1 ==== B		IPv6-over-IPv4 tunnel between A and B
To allow IPv6-over-IPv4 tunnel to go through FW-1, please take the following steps:
  1. Create new srevice called "IPv6-over-IPv4", with service type "Other".
  2. Add "Match" with "ip_p = 41".
  3. Now you have this configuration, which allows packets with IPv4 protocol type of 41 to go through, but no others.
    rule    Src     Dst    Service         Action
    1       A,B     B,A    IPv6-over-IPv4  Accept
    2       A,B     B,A    Any             Reject
If you can make it more loose, you can allow any packet between A and B to go through, like:
rule    Src     Dst     Service Action
1       A,B      B,A    Any     Accept

Securing 6bone connection

While 6bone is still a small network, it is good to be cautious. You may want to implement IPv6 packet filters onto your 6bone connection. KAME for FreeBSD228 and FreeBSD32 includes ip6fw, which is capable of filtering IPv6 packet. You may want to configure this into your inbound IPv6 router.

Also, KAME kit includes ports/pkgsrc directory for IPv6-ready fwtk, Coutesy of Mr. Hajime Umemoto. You would like to have tcp relay, this is the answer. But if you implement fwtk, you cannot enjoy direct IPv6 connection from your end node to outside.

Please note that NAT provides no security at all, so there will be no IPv6-to-IPv6 NAT.