I configured apache much like: http://linux.yyz.us/ipv6/proxy.html with a few differences

1. I didnt use NameVirtualHost, just put a specific IP in. NameVirtualHosts just feel a bit unnecessary with IPv6, and this way i can point several aliases at the entry without defining them all. This may be considered a small security issue, as other people could point their illegitimate domain names at your site and it would still work and look official.

2. So i didnt have to register all of the aliases, i did not enable ProxyPreserveHost

3. As bryars.eu would resolve to AAAA and A, I didn’t want Apache to get in a loop and proxy to itself, so i added an alias v4 to ensure v4 only forwarding.

For some reason it was sending 301 redirects until the DNS was all sorted

# Contents of /etc/apache2/sites-available/bryars.eu-proxy
<VirtualHost [2001:470:9272:1::2]>
 ServerName bryars.eu
 CustomLog /var/log/apache2/bryars.eu-proxy.log combined

 ProxyRequests Off
 <proxy http://v4.bryars.eu/*>
 Order deny,allow
 Allow from all
 </proxy>
 ProxyPass             /       http://v4.bryars.eu/
 ProxyPassReverse      /       http://v4.bryars.eu/
</VirtualHost>

Also added the IP address to my /etc/network/interfaces so it would get allocated when the tunnel came up, by adding the following line to my tunnel interface stanza:

up ip addr add 2001:470:9272:1::2/64 dev $IFACE preferred_lft 0

The preferred_lft 0 is to mark the ip as deprecated so it doesn’t get used as the default address for outgoing connections. For more information see: http://www.davidc.net/networking/ipv6-source-address-selection-linux

If due to a misconfiguration a v4tunnel interface you have brought up with ifup has failed, you need to manually delete it before trying again or this annoying error will happen:


# ifup somev6tunnel
ioctl: No buffer space available
# ip tunnel del somev6tunnel
# ifup somev6tunnel
#


I was trying to configure a 6to4 tunnel but without specifying a local interface address by using local any endpoint any, but that gives an unhelpful and yet increasingly familiar error message.


# ifup 6to4
ioctl: No buffer space available


Linux doesn’t like both local and remote values unset, so I thought, aha I’ll just use local any endpoint 192.88.99.1, it appeared to work. I have since realised that it only works for talking to non 6to4 hosts, if I tried to talk to another 6to4 host, it routed the packets through the gateway instead of directly and the return packets were also lost. So, I just specified the local address and it works.

My working 6to4 debian /etc/network/interfaces


auto 6to4
iface 6to4 inet6 v4tunnel
address 2002:561e:XXXX::1 # ipv6calc -I ipv4addr -O ipv6addr -A conv6to4 86.30.XX.XX
netmask 16
local 192.168.1.2 # address assigned by wifi router
endpoint any
gateway ::192.88.99.1 # 6to4 anycast address


Though its best to use a managed tunnel, like Hurricane Electrics tunnelbroker.net

The is the Debian network interfaces config i used to connect to my tunnelbroker.net ipv6 tunnel, reconfigure the tunnel endpoint dynamically, and also add one of my routed /48 subnets to the interface (so i can use pretty reverse dns addresses from my host).


auto he-ipv6
iface he-ipv6 inet6 v4tunnel
address 2001:470:1f08:xxxx::2
netmask 64
endpoint 216.66.80.26
gateway ::216.66.80.26
# Docs to generate pass etc from http://ipv4.tunnelbroker.net/ipv4_end.php
up wget --no-check-certificate -O - 'https://ipv4.tunnelbroker.net/ipv4_end.php?ipv4b=AUTO&pass=9c4db7a186c8xxxxxxxxxxxxxx&user_id=ef2ffab0c775dxxxxxx&tunnel_id=19xxx' 2>/dev/null
up ip addr add 2001:470:XXXX:1::1/64 dev $IFACE


Highly recommend working your way through their course if this interests you.