Since version 2.0 of Bering-uClibc IPv6 is an officially supported feature. In previous versions of Bering-uClibc and in "plain" Bering very limited IPv6 functionality was available using the ipv6.o kernel module and the ip command, but no IPv6 applications were provided.

The IPv6 support of Bering-uClibc consists of

This chapter consists of two parts. In the next section the IPv6 configuration of Bering-uClibc is described. The rest of the sections contain application specific notes regarding IPv6.

These instructions are for those who want to use their Bering-uClibc system not only as an IPv4 router/firewall but also as an IPv6 router/firewall. This document assumes that you already have a some knowledge about Bering-uClibc.

A good start for more information on IPv6 is the Linux IPv6 HOWTO and Peter Bieringer's IPv6 & Linux - HowTo.

In order to have IPv6 working, you need to have IPv6 support enabled through the appropriate kernel module: kernel/net/ipv6/ipv6.o. There are two ways to do this:

(...)
# IPv6 support
ipv6
(...)

Bering-uClibc -root-
# ip addr
1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 brd 127.255.255.255 scope host lo
    inet6 ::1/128 scope host
2: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
3: eth0: <BROADCAST,MULTICAST,UP>> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:40:95:1a:14:f4 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.120/24 brd 10.0.0.255 scope global eth0
    inet6 fe80::240:95ff:fe1a:14f4/10 scope link
4: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:40:95:1a:14:70 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.254/24 brd 192.168.1.255 scope global eth1
    inet6 fe80::240:95ff:fe1a:1470/10 scope link
5: sit0@NONE: <NOARP> mtu 1480 qdisc noop
    link/sit 0.0.0.0 brd 0.0.0.0
            

Copy the the following packages to one of your floppies:

These packages are provided in the IPv6 drop-in tarball which can be downloaded from the Sourceforge FRS.

Detailed information on how to add packages to your system can be found in the Bering-uClibc Installation Guide.

Modify the lrpkg.cfg file to load the new packages.

root,etc,local,modules,ppp,dnscache,weblet,iptables,shorwall,radvd,ip6table,6wall
        

If all worked well, you should have seen some IPv6 addresses (inet6) appear on your interfaces in previous step. All these addresses have scope "local", this means that these are link-local addresses and can only be used on the network segment to which the interface is connected. But since you're working with a Bering-uClibc router it's highly unlikely that your network consists only of one segment, but rather of two or more.

If you want hosts on different segments to communicate with each other using IPv6, you need to assign these hosts either site-local or global addresses. global addresses need to be assigned to you by an ISP and site-local addresses are your to use freely within your own network (like the RFC1918 addresses for IPv4). Therefore, we'll start using site-local addresses first. If you have global addresses and don't want to use site-local addresses, you can skip this section and go directly to Step 6: Configure a 6to4 tunnel.

The prefixes used in this example are:

Invoke lrcfg and choose 1) Network configuration and then 1) Network Interfaces. In the interface file add an IPv6 address for your each of your interfaces that corresponds with the prefix for the interface.

(...)
iface eth0 inet6 static
	address fec0:1::1
	masklen 64

iface eth1 inet6 static
	address fec0:2::1
	masklen 64
(...)
        

Next, within lrcfg choose 2) Network options file. In this config file IPv6 forwarding can be enabled, which is nice for a router ;-).

(...)
ipv6_forward=yes        
(...)
        

The effect of this configuration item is that on start-up the command echo 1 > /proc/sys/net/ipv6/conf/all/forwarding is given.

One of the features of IPv6 is the router advertisement mechanism. When a router advertises the network prefix to be used on a network segment, hosts on that segment can use the advertised prefix to automagically configure an IPv6 address. The router advertisement messages are also used by the hosts to configure the gateway address.

The radvd.lrp package contains a router advertisement daemon for Bering-uClibc. The configuration of the daemon is very straight forward. If in our example we want to use router advertisement on eth1, edit the /etc/radvd.conf file as follows:

interface eth1
{
        AdvSendAdvert on;
        prefix fec0:2::/64
        {
                AdvOnLink on;
                AdvAutonomous on;
        };
};
        

Check the ip addresses and the routing table with the following commands:

Bering-uClibc -root-
# ip -6 addr
1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
    inet6 ::1/128 scope host
3: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    inet6 fec0:1::1/64 scope site
    inet6 fe80::240:95ff:fe1a:14f4/10 scope link
4: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    inet6 fec0:2::1/64 scope site
    inet6 fe80::240:95ff:fe1a:1470/10 scope link

Bering-uClibc -root-
# ip -6 route
fe80::/10 dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440
fe80::/10 dev eth1  proto kernel  metric 256  mtu 1500 advmss 1440
fec0:1::/64 dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440
fec0:2::/64 dev eth1  proto kernel  metric 256  mtu 1500 advmss 1440
ff00::/8 dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440
ff00::/8 dev eth1  proto kernel  metric 256  mtu 1500 advmss 1440
unreachable default dev lo  metric -1  error -101

Bering-uClibc -root-
# cat /proc/sys/net/ipv6/conf/all/forwarding
1
        

Now an IPv6 capable system (how to configure IPv6 on Win XP) in one segment of your network should now be able to ping6 another IPv6 system in another segment connected to the router. Both should also be able to ping6 the router.

Ping6 is the IPv6 equivalent of ping and is provided by the initrd.lrp package.

In the most luxurious case you have a native IPv6 connection to the internet. In that case you can follow Step 4 and 5 and substitute the site-local addresses used with your global addresses. if you're not that lucky, IPv6 access to the Internet can be achieved via a tunnelbroker (see Section - Prerequisites). You will get the necessary global addresses and prefix(es) from the tunnelbroker. This is what will be described below.

When connecting via a tunnelbroker, an IPv6-to-IPv4 (6to4) tunnel is established between your gateway and the tunnelbroker. To setup this tunnel you need the following information (imaginary information is given for the example):

Edit /etc/network/interfaces as follows:

(...)
#
# Definition of the Ipv6-to-IPv4 tunnel interface
#
#auto tun6to4
iface tun6to4 inet6 v4tunnel
	address 3ffe:8280:0:2001::2
	netmask 64
	gateway 3ffe:8280:0:2001::1
	endpoint 202.143.23.6
	ttl 254
(...)
        

You need to allow the 6to4 tunnel traffic from the Bering-uClibc Firewall to the tunnelbroker. This traffic uses IP protocol 41.

With Shorewall 1.4.3 and later you can add a 6to4 tunnel definition in the /etc/shorewall/tunnels file. In the examples below it is assumed that your firewall zone is called "fw" and the Internet zone "net".

#TYPE    ZONE   GATEWAY        GATEWAY ZONE 
(...)
6to4     net    202.143.23.6
(...)
        

More information on Shorewall and 6to4 tunnels can be found in the Shorewall documentation.

For versions older than 1.4.3 you can add some rules in the /etc/shorewall/rules file.

#ACTION  SOURCE             DEST              PROTO   DEST    SOURCE     ORIGINAL
#                                                     PORT    PORT(S)    DEST
(...)
#
# Accept 6to4 tunnel traffic from the firewall to tunnelbroker
#
ACCEPT   fw                 net:202.143.23.6  41
ACCEPT   net:202.143.23.6   fw                41
(...)
        

After restarting Shorewall, you should be able to ping6 or traceroute6 to IPv6 accessible hosts on the Internet. Some hosts that you could try are:

In the following it is assumed that your local network is connected to eth1 and that the connection to the internet (over which the 6to4 tunnel will be established) goes via eth0.

Based on the information from your tunnelbroker, select the prefix of /64 to be used on the network segment connected to eth1. Then edit /etc/network/interfaces as follows:

(...)
iface eth1 inet6 static
	address fec0:2::1
	masklen 64
	up ip addr add 3ffe:8280:10:8560::1/64 dev eth1
(...)
        

To advertise the selected global prefix as well as the site-local prefix from Step 4, edit the /etc/radvd.conf file as follows:

interface eth1
{
        AdvSendAdvert on;
        prefix fec0:2::/64
        {
                AdvOnLink on;
                AdvAutonomous on;
        };
        prefix 3ffe:8280:10:8560::/64
        {
                AdvOnLink on;
                AdvAutonomous on;
        };
};
        

After restarting the Router Advertisement daemon, any systems running on your local network that support autconfiguration for IPv6, they should be getting a global IPv6 address. If not, maybe the system needs to be rebooted first.

When a system on the local network has configured a global IPv6 address, it should now also be able to ping6 and traceroute6 to the hosts mentioned in Step 7.

6wall is for IPv6 what Shorewall is for IPv4.

6wall is an IPv6 firewall which is derived from Shorewall version 1.4. So if you're familiar with Shorewall you should have no problem configuring 6wall. The best way to start is to read-up on Tom Eastep's excellent Shorewall documentation. After that, check the 6wall documentation where specific issues for 6wall are described.

When you're done reading, you can configure 6wall. Go to the packages menu and select 6wall. The following menu will appear:

                        6wall configuration files

        1) Zones     Partition the network into Zones
        2) Ifaces    6wall Networking Interfaces
        3) Hosts     Define specific zones
        4) Policy    Firewall high-level policy
        5) Rules     Exceptions to policy
        6) Maclist   MAC verification
        7) Config    6wall Global Parameters
        8) Blacklist Blacklisted hosts
        9) SiteLocal Defines 'nositelocal' interface option
        10) Common    Common rules
        11) Init      Commands executed before [re]start
        12) Start     Commands executed after [re]start
        13) Stop      Commands executed before stop
        14) Stopped   Commands executed after stop

  q) quit
  ----------------------------------------------------------------------------
        Selection:
        

The configuration files that can be edited via the menu above are located in the /etc/6wall/ directory. Below is the default configuration of some of these files.

The zones for IPv6 are described in zones6:

#ZONE   DISPLAY         COMMENTS
net     Net             Internet
loc     Local           Local networks
        

The interfaces for IPv6 are described in interfaces6:

#ZONE    INTERFACE      OPTIONS
net      tun6to4        nositelocal
loc      eth1
        

The policies for IPv6 are described in policy6:

#SOURCE         DEST            POLICY          LOG LEVEL
loc             net             ACCEPT            
net             all             DROP              info
all             all             DROP              info
        

The rules for IPv6 are described in rules6:

#ACTION  SOURCE         DEST            PROTO   DEST    SOURCE     ORIGINAL
#                                               PORT    PORT(S)    DEST
#
#       Allow ping6 from the firewall
#
ACCEPT   fw             all             icmpv6  echo-request
#
#
#       Allow ping6 from the local network to the firewall
#
ACCEPT   loc            fw              icmpv6  echo-request
        

This configuration should get you started and you can modify these or other configuration files to suit your needs.

Now reboot your system and enjoy safe surfing on the IPv6 Internet !!

To be provided.....

A number of applications are IPv6 specific while others are generic but with IPv6 support enabled. below an overview of the IPv6 (enabled) applications in Bering-uClibc is given. The following sections will go into the IPv6 specifics of these applications.