My ISP has just started IPv4/IPv6 dual stack service. In order to connect IPv4/IPv6 internet, almost all users usually use a CPE leased by the ISP. But I want to use my Linux router instead of such CPE, because my router has so many roles(a lot of iptables rules and 3 Ethernet interfaces, http reverse proxy, http cache, memcached, smtp/pop server and DNS proxy). I want to let it to be an IPv4/IPv6 dual stack router.
My router
- CentOS6.0 i686
- eth0 for WAN
- eth1,2 for LAN
- ISC dhcp(version 4.1.1) installed by "# yum install dhcp" from CentOS-updates repo
- radvd(version 1.6) installed by "# yum install radvd" from CentOS-base repo
- [EDIT] The reason why I use ISC dhclient is that my router has to send a DHCPv6 option 16 (Vendor class) in its solicit and request messages, in order to get vendor-specific-information option which includes some ISP-specific informations(SIP phone number, firmware server address). I know how to set option 16 in ISC dhclient, but don't know it in WIDE-dhcpv6. And I can not find such settings as "id-assoc" in ISC dhclient.
My goal
- /48 prefix is delegated to DHCPv6-PD(DHCPv6 Prefix Delegation) client(dhclient) on eth0.
- An IPv6 default route is set toward to ISP. I have to consider ISP's DHCPv6 server's link-local address as a default route.
- One /64 subnet and one global address (which are in the delegated prefix) are assigned to each LAN I/F(eth1/eth2).
- radvd on eth1 and eth2 announces RA based on the assigned /64 subnet.
- dhcpd6 on eth1 and eth2 announces additional network information(name-servers, domain-searchlist and sip-servers-addresses) received from ISP's DHCPv6 server.
My current configuration
/etc/sysconfig/network
NETWORKING=yes
HOSTNAME=xxx.yyy.zzz
# Enable IPv6 routing and stop accept_ra/autoconf.
IPV6FORWARDING=yes
/etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE="eth0"
ONBOOT=yes
TYPE=Ethernet
BOOTPROTO=none
# Enable DHCPv6-PD client.
DHCPV6C=yes
DHCPV6C_OPTIONS="-P -cf /etc/dhcp/dhclient6.conf"
# Disable make_resolv_conf function in /sbin/dhclient-script.
PEERDNS=no
/etc/dhcp/dhclient6.conf
script "/sbin/dhclient-script";
interface "eth0" {
send dhcp6.reconf-accept;
also request dhcp6.vendor-opts, dhcp6.sip-servers-names, dhcp6.sip-servers-addresses, dhcp6.sntp-servers;
}
Result
After "# service network restart", DHCPv6-PD client seems to finish successfully.
lease6 {
interface "eth0";
ia-pd xx:xx:xx:xx {
starts 1312464004;
renew 7200;
rebind 10800;
iaprefix 24xx:xxxx:xxxx::/48 {
starts 1312464004;
preferred-life 12600;
max-life 14400;
}
}
option dhcp6.client-id xx:xx:xx:xx:xx:xx:xx:xx:xx:xx;
option dhcp6.server-id xx:xx:xx:xx:xx:xx:xx:xx:xx:xx;
option dhcp6.reconf-accept ;
option dhcp6.sip-servers-addresses 24xx:xxxx:xxxx:xxxx::1;
option dhcp6.name-servers 24xx:xxxx:xxxx:xxxx::3,24xx:xxxx:xxxx:b::3;
option dhcp6.domain-search "xxx.jp.", "yyy.jp.";
option dhcp6.sntp-servers 24xx:xxxx:xxxx:xxxx::a,24xx:xxxx:xxxx:b::b;
}
Question
DHCPv6-PD client is delegated /48 prefix successfully. But after that,
- How to set an IPv6 default route in the router's routing table ?
- How to assign a global IPv6 address and /64 subnet to each LAN I/F(eth1 and eth2) based on the delegated prefix ?
- How to trigger radvd to announce RA on each LAN I/F(eth1 and eth2) ?
- How to trigger DHCPv6 server(dhcpd6) on each LAN I/F to announce additional network information(name-servers, domain-searchlist and sip-servers-addresses) received from ISP's DHCPv6 server ?
My guess
According to "$ man dhclient" and "$ man dhclient-script", dhclient-script seems to be used to configure such settings, and it offers some hooks. But now, it does nothing for DHCPv6-PD client.
Yes, I may have to write some scripts suitable for my DHCPv6-PD environment, though I am not familiar with IPv6 network configurations. Anyone let me know the above settings in dhclient-script ? [EDIT] I want to know the practical dhclient-script.
And I worry, some special consideration should be taken. For example, because each IPv6 address has preferred/valid lifetime, when I assign a global IPv6 address to a LAN interface based on the delegated prefix, I have to assign not only an IPv6 address but also its lifetimes which must be derived from the delegated prefix's preferred/valid lifetimes ?
Also, radvd and DHCPv6 server on LAN interfaces may have to be re-configured when DHCPv6 re-configuration happens ? Which hook should be used ?
[EDIT] When DHCPv6 re-configuration happens, how to announce both new and obsolete information ? radvd automatically announce the previous prefix is obsolete? DHCPv6 server automatically announce the previous name-servers are obsolete ?
