git-svn-id: https://map66.svn.sourceforge.net/svnroot/map66@26 3484d885-4da6-438d-b19d-107d078dd756

1 files changed, 26 insertions, 2 deletions

diff --git a/README.txt b/README.txt
index 9ea1734..399a38a 100644
--- a/README.txt
+++ b/README.txt
@@ -18,6 +18,10 @@ Configuration
     Detailed Version
 
 IPv6/IPv4 Precedence
+
+    Change gai.conf
+    Use 6to4 Internal Address
+
 Motivation
 
 These files implement a Linux netfilter target that changes the IPv6 address of
@@ -202,9 +206,10 @@ pre-installed /etc/gai.conf file will give you a hint on this.
 In short: the getaddrinfo() library function rates a private IPv4 address
 higher than the ULA IPv6 address when choosing the transport protocol for a new
 Internet connection if this add on to the RFC 3484 rules is compiled in. For
-this reason, you may want to change the precedence rules within /etc/gai.conf.
+this reason, you may want to change the precedence rules within /etc/gai.conf
+(see Change gai.conf) or use another prefix (see Use 6to4 Internal Address).
 
-Note
+Change gai.conf
 
 The getaddrinfo() library function manages lists of label, precedence, and
 scope4 type entries. If the /etc/gai.conf file does not provide a single entry
@@ -230,6 +235,25 @@ The above procedure removes the difference between standard IPv6 source
 addresses and ULA type private IPv6 source addresses. Anything else is
 unchanged.
 
+Use 6to4 Internal Address
+
+As an alternative solution, you may use 6to4 addresses in your LAN. While the
+well known IPv4 adresses 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 still
+exist, it is unlikely that their 6to4 counterparts 2002:0a00::/24, 2002:ac10::/
+28, and 2002:c0a8::/32 will be routed on the Internet. Because 6to4 adresses
+are part of the official 2002::/3 address prefix for the Internet, no
+difference between these addresses and other Internet addresses are made by
+getaddrinfo().
+
+If you already deployed ULA adresses in your network, you may be interested in
+a solution that runs on my Freifunk router. The router uses the IPv4
+192.168.65.65/26 on it's LAN interface. WIthin the OLSR-based mesh network, any
+interface uses an fdca:ffee:babe::/64 prefix. The following internal mapping is
+configured for this:
+
+ip6tables -t mangle -I PREROUTING -i br0 -s 2002:c0a8:4141::/64 -j MAP66 --src-to fdca:ffee:babe::/64 --unbalanced
+ip6tables -t mangle -I POSTROUTING -o br0 -d fdca:ffee:babe::/64 -j MAP66 --dst-to 2002:c0a8:4141::/64 --unbalanced
+
 Motivation
 
 My Internet access at home is realized by a wireless community mesh network not