IPv6 setup issues, pls help

Question

I'm trying to setup my ipv6 on my raspberry pi 4. Now when I reboot it with fritzbox set to 6to4 I can't access my raspberry any more from my network (ssh, webmin etc). Additionally I can't access the pi any more with wlan0. On the other side the pi is up, its ipv6 address would show the apache standard page!

If I reboot again with the fritzbox set to ipv4 I can access the raspberry again. What do I need to change to get it running with ip 6to4?

Thanks Marc

I've got:

root@raspberrypi:/etc#  grep -v '^[#\ ]' <dnsmasq.conf
domain-needed
bogus-priv
server=2001:4860:4860::6464
except-interface=eth0
bind-interfaces
domain=mywlan
dhcp-fqdn
enable-ra
dhcp-option=option6:dns-server,[2001:4860:4860::6464]
dhcp-authoritative
dhcp-mac=set:client_is_a_pi,B8:27:EB:*:*:*
dhcp-reply-delay=tag:client_is_a_pi,2
interface=wlan0
listen-address=127.0.0.1,192.168.2.1
dhcp-range=192.168.2.2,192.168.2.255,12h
dhcp-range=::100,::1ff,constructor:wlan0,ra-names,slaac

dhcp-host=xxxxx,MiA1,192.168.2.105
dhcp-host=xxxxx,RedMi,192.168.2.106

and

root@raspberrypi:/etc#  grep -v '^[#\ ]' < dhcpcd.conf
hostname
clientid
persistent
option rapid_commit
option domain_name_servers, domain_name, domain_search, host_name
option classless_static_routes
option interface_mtu
option ntp_servers
require dhcp_server_identifier
slaac private
interface eth0
inform 192.168.1.1
interface wlan0

route -A inet6 shows

 /sbin/route -A inet6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
localhost/128                  [::]                       U    256 2     0 lo
2002:xxxx:yyyy::/64            [::]                       U    202 1     0 eth0
fe80::/64                      [::]                       U    256 1     0 tun0
fe80::/64                      [::]                       U    256 1     0 wlan0
fe80::/64                      [::]                       U    256 1     0 eth0
[::]/0                         [::]                       !n   -1  1     0 lo
localhost/128                  [::]                       Un   0   6     0 lo
2002:xxxx:yyyy::/128           [::]                       Un   0   3     0 eth0
raspberrypi.fritz.box/128      [::]                       Un   0   3     0 eth0
fe80::/128                     [::]                       Un   0   5     0 tun0
fe80::/128                     [::]                       Un   0   3     0 wlan0
fe80::/128                     [::]                       Un   0   3     0 eth0
fe80::957:595:c08b:d0bd/128    [::]                       Un   0   3     0 eth0
fe80::411c:7d49:88da:4326/128  [::]                       Un   0   3     0 tun0
fe80::81af:f6c3:3823:9efb/128  [::]                       Un   0   2     0 wlan0
ff00::/8                       [::]                       U    256 6     0 wlan0
ff00::/8                       [::]                       U    256 1     0 tun0
ff00::/8                       [::]                       U    256 5     0 eth0
[::]/0                         [::]                       !n   -1  1     0 lo

And cat /etc/host

    root@raspberrypi:/etc# cat /etc/hosts
    127.0.0.1       localhost
    ::1             localhost ip6-localhost ip6-loopback
    ff02::1         ip6-allnodes
    ff02::2         ip6-allrouters
    
    127.0.1.1               raspberrypi

ip a

root@raspberrypi:/etc# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether dc:a6:32:ea:e8:6a brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.1/24 brd 192.168.1.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 fd00::xxxxxxxxxxxxxxx/64 scope global dynamic mngtmpaddr noprefixroute
       valid_lft 6859sec preferred_lft 3259sec
    inet6 2002:xxxxxxxxxxxxxxx/64 scope global deprecated dynamic mngtmpaddr noprefixroute
       valid_lft 1633sec preferred_lft 0sec
    inet6 fe80::xxxxxxxxxxxxxxx/64 scope link
       valid_lft forever preferred_lft forever
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether dc:a6:32:ea:e8:6b brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.1/24 brd 192.168.2.255 scope global noprefixroute wlan0
       valid_lft forever preferred_lft forever
    inet6 fe80::xxxxxxxxxxxxxxx/64 scope link
       valid_lft forever preferred_lft forever
4: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 100
    link/none
    inet 10.8.0.1 peer 10.8.0.2/32 scope global tun0
       valid_lft forever preferred_lft forever
    inet6 fe80::xxxxxxxxxxxxxxx/64 scope link stable-privacy
       valid_lft forever preferred_lft forever

Answer 1

The following is for my RPi-4 as a my home router.

My /etc/dhcpcd.conf is essentially yours except for:

    `interface eth0
 ipv4
 ipv6
 dhcp
 dhcp6
 ipv6rs                               # enable routing solicitation get the
                                      # default IPv6 route
 ia_na 1 eth0                         # request an IPv6 address
 ia_pd 1/::/64 enx0050b6eab7d6/0/64   # request a PD and assign it to enp1s0u1u2'

eth0 is to Comcast's ipv6 server and the enx.... is a USB Ethernet dongle.

This jams a 1 onto the enx ipv6 address address giving 2601:x:y:z::1 on the dongle Ethernet.

Use the command as root to see what the Ethernet interfaces(s) have assigned:

    `/sbin/dhcpcd -6 -U eth0
    

This -U is the key. It took me 3 months to find that detail! The -U publishes a lot of information, both IPv4 and IPv6.

dnsmasq has the builtin ability to read all files in a folder. I use the following shell script to set up the dnsmasq ipv6 SLAAC portion for my home network. This assigns IPv6 to phones, pads etc. I haven't bothered to put this in an automatic boot script yet. I log in quickly and run it by hand.

    `#!/bin/bash -xv

     base_prefix=$(/sbin/dhcpcd -6 -U eth0 | grep "dhcp6_ia_pd1_prefix1="   | cut -d '=' -f 2 | cut -d : -f 1-4 | cut -d "'" -f 2)

     #   echo $base_prefix

     # following sets up router advertizements for dnsmasq
     #   ie:  dnsmasq reads this file to get the ipv6 network ip6 base prefix numbers

     echo "dhcp-range="$base_prefix":0:0:0:500,"$base_prefix":FFFF:FFFF:FFFF:FFFF, ra-names, 150" >/etc/dnsmasq.d/router-advertise.conf

    # scanned from ifconfig enx0050b6eab7d6 device 

    link_ip=$(ip address show dev enx0050b6eab7d6 scope link | awk '/inet6 / {split($2,var,"/"); print var[1]}')
    echo "dhcp-option=option6:dns-server,[${link_ip}]"  >/etc/dnsmasq.d/local-dns-server.conf


     /etc/init.d/dnsmasq restart

    exit 0`

The SLAAC addresses timeout every 150 seconds. I also reserve 500 IPv6 address for my own use, none of which I am using. IPv6 documentation suggest you use the fdxx addresses for host IP addresses in local network.

An example of my /etc/hosts file is:

   `192.168.200.11      ruby.lan   ruby
    fe80::xx.yy.zz      ruby6.lan   ruby6`

I haven't found a way to use a single hostname to serve up both IP numbers. In my case one of my machines is called ruby for IPv4, and ruby6 for IPv6.

I set my network MTU using dnsmasq to 1412 because of the comment at the bottom of "man pppoe". And I no longer get network stalling for movies, etc. Comcast is my ISP and their default is 1500.