Routed /64

[viperlight]

Hi Guys,

I'm trying to get my head around the whole ipv6 address allocation with HE. When you sign up for tunnel you are given a /64 straight up which is great :). Am I correct in assuming this subnet will always be assigned to your tunnel interface (ios speaking) and you would need to apply for a routed /48 to apply onto the vlan or fastethernet if you wan to service hosts on the lan.

It seems like the /64 is a waste as it is being utilised only as a point to point link. Is this correct?

Cheers,

[cholzhauer]

Well, you're actually assigned two /64's  off the bat, but you only can really use one of them.

One of the /64 is the tunnel interface [::1 (HE end) and ::2 (your end)]  Is this a waste? I think so, but in IPv6 thinking, it's not. 

You're also assigned a routed /64 which you can use for a subnet (a la 192.168.1.0/24)  If you need to have more than one subnet, you request the /48

[allen4names]

cholzhauer

There are three /128s out of the allocated /64 that can not be used if I am not mistaken. Here is a list including a fourth if you have an IPv6 enabled router.

* 2001:470:a:18f:: - For DHCPv6
* 2001:470:a:18f::1 - Remote tunnel endpoint
* 2001:470:a:18f::2 - Local tunnel endpoint (at an IPv6 router)
* 2001:470:a:18f:ffff:ffff:ffff:ffff - Reserved anycast address

2001:470:a:18f:0:41:6c6c:656e (Allen, address not used yet)

[viperlight]

Thanks for the reply :)

Technically speaking aren't ::1 and ::2 in the same /64 hence you really only get 1 initial /64 ?

[cholzhauer]

The way it's "supposed" to work:

On your tunnel page, there are lines for Server IPv6 address and Client IPv6 address.  You will notice these are from the same network.  Now we're done with this network

A little further down, you see a Routed /64.  You use this to assign IP addresses to your clients on one subnet.

Can you use IP's from the tunnel network?  Yes, but you probably shouldn't.  HE doesn't delegate these for reverse DNS, and depending what you want to do with your hosts, could cause problems later.

[viperlight]

Holy crap!

How did I miss that. Damn 1 hex character difference lol :)