multihomed server with ipv6

[lists@onemanifest.net]

Hi all,


I’m trying to setup a multi-homed server with dual stack networking.

I’ve setup static adressing for both NICs for ipv4 and ipv6 like this:

  # The primary LAN network interface
  allow-hotplug eth0
  iface eth0 inet static
    address 192.168.1.xx
    netmask 255.255.255.0
    network 192.168.1.0
    broadcast 192.168.1.255
    gateway 192.168.1.1
    # dns-* options are implemented by the resolvconf package, if installed
    dns-nameservers 192.168.1.1
    dns-search somedomain.tld
  
  iface eth0 inet6 static
    address 2001:xxxx:xxxx:3::20
    netmask 64
    gateway 2001:xxxx:xxxx:3::1
    dns-nameservers 2001:xxxx:xxxx:3::1
    dns-search somedomain.tld
  
  
  # The secondary DMZ network interface
  allow-hotplug eth1
  iface eth1 inet static
    address 192.168.0.xx
    netmask 255.255.255.0
    network 192.168.0.0
    broadcast 192.168.0.255
    gateway 192.168.0.1
    # dns-* options are implemented by the resolvconf package, if installed
    dns-nameservers 192.168.0.1
    dns-search somedomain.tld
  
  iface eth1 inet6 static
    address 2001:xxxx:xxxx:2::20
    netmask 64
    gateway 2001:xxxx:xxxx:2::1
    dns-nameservers 2001:xxxx:xxxx:2::1
    dns-search somedomain.tld
    
The NICs are configured fine, but only _one_ ipv6 gets assigned. After a reboot either
eth0 or eth1 gets it’s ipv6 assigned, never both. I can add the missing ip manually with 

  ip -6 addr add 2001:xxxx:xxxx:2::20/64 dev eth1 

But I can’t get it to be assigned automatically. What am I doing wrong here? I’ve been googling for multi homed servers, but can’t find anything on this issue.

Also, I noticed that if I ping6 a host is subnet A from a NIC in subnet B, the servers ip6 in subnet A is used as source ip, even if an ipv6 in subnet B is available on that NIC. Does this mean that the return traffic is routed over subnet A in stead of B? This is not desirable since I’d like the traffic between both subnets to be fire-walled by the router.


Thanks