Need some help with subnetting

[chiel]

Hello,

I'm currently using a /64 tunnel on my router. This works good.
Because I wanted to also have a IPv6 only interface on the router I thought I just subnet this /64 into two subnets (vlan1: dualstack - vlan2: ipv6 only). Is this possible? Because I see on many websites that /64 is the smallest subnet for IPv6.

And I just noticed that you can also request an /48 from HE. Is that for this purpose? And wouldn't this conflict with the /64 that is already allocated? I don't see a option to delete this /64 once I have allocated the /48.

[cholzhauer]

I thought I just subnet this /64 into two subnets (vlan1: dualstack - vlan2: ipv6 only). Is this possible?

Maybe, but you don't want to.

And I just noticed that you can also request an /48 from HE. Is that for this purpose?

Yes

And wouldn't this conflict with the /64 that is already allocated?

no

 I don't see a option to delete this /64 once I have allocated the /48.

you don't want to.

the /64 is the transport network for your tunnel, the /48 is what you divide up into multiple /64's to assign to your network

[jimb]

You actually get two /64s, one for the tunnel itself, and a routed 64.  If you request a /48 you can still use the routed /64 as well as any /64s you break out of the /48.  No conflict.

[cholzhauer]

Whoops, I didn't know you were assigned two /64's right from the start.

Thanks for the correction, Jim

[chiel]

Thanks for the reply's, its working now.
Just one question still: Is it correct that autconfiguration only works with a /64 on a network? Because when I first assigned the whole /48 it didn't work.

[broquea]

Thanks for the reply's, its working now.
Just one question still: Is it correct that autconfiguration only works with a /64 on a network? Because when I first assigned the whole /48 it didn't work.

correct, /64 for RA