Since my previous Asus WL-500gP was broken due to a power outage, it was time for a new one. Some requirements for a new router where; IPv6, 802.11a/n and gigabit Ethernet switch ports. The Asus only had the IPv6 requirement since I installed OpenWrt on it.
The Cisco EA4500 was one that supports all this. Since I quickly needed a new router I bought this one at a local reseller.
I installed this router at home and found out that this router supports native IPv6, but only via auto-configuration and DHCPv6. Manual IPv6 addresses cannot be configured and static IPv6 routing is also not an option.
Since my previous setup was static routing with IPv6, I needed some changes on the Internet Service Provider side. Luckily I do the configuration and administration for this ISP as a day job. So I introduced DHCPv6 as a configuration option for customers.
This is very easy to setup. The router on the ISP site is an Cisco ASR 1002, with an ATM interface to a DSL provider.
First the configuration for static IPv6 routing was as follow (only IPv6 relevant commands):
interface ATMx/x/x.xx point-to-point atm route-bridged ipv6 ipv6 address 2001:xxxx:xxxx:xxxx::x/64 ipv6 enable ! ipv6 route 2001:xxxx:xxxx:xxxx::/64 ATMx/x/x.xx 2001:xxxx:xxxx:xxxx::x
Now the configuration with DHCPv6 is (again only IPv6 relevant commands):
interface ATMx/x/x.xx point-to-point atm route-bridged ipv6 ipv6 address 2001:xxxx:xxxx:xxxx::x/64 ipv6 enable ipv6 nd other-config-flag ipv6 dhcp server ipv6-dhcp-pool ! ipv6 dhcp pool ipv6-dhcp-pool prefix-delegation 2001:xxxx:xxxx:xxxx::/64 xxxxxxxxxxxxxxxxxxxxxxxx dns-server 2001:xxxx:xxxx:xxxx:x dns-server 2001:xxxx:xxxx:xxxx:x
The EA4500 on the client side does a DHCPv6 request. The ASR on the ISP side replies and sends a prefix for the local LAN side and the DNS servers. The EA4500 advertises the /64 prefix and its own IPv6 address for DNS resolving on the local LAN via router advertisements (RA).