ipv6 - New subnet mask too short

Bruce Hudson Bruce.Hudson at Dal.Ca
Fri Oct 26 22:03:42 UTC 2012

> Well, they do overlap now. Just fro the '1' part, not the '5' or '6' part
> as those are your different subnets within the space.

> Do you really want to hubs out /112 either than /64 though?

    Do I want to? No. I was taught that the only valid IPv6 subnet masks
for a "physical network" were "/64" and "/127" (a special case for point
to point links). You specified the "/112" mask. I am not sure how far
various software supports non-standard masks so I just assumed what you
had would do so and went with it.

    I was just trying to figure out what your topology looks like, as it 
affects your DHCP configuration. Do you want a single shared-network
spanning multiple interfaces or does each interface have is own LAN? Is
your server acting as a switch or a router (or both or neither)?

>  V6 isn't like v4 regarding submitting down to that level....

    The basics are the same. Each subnet has to exist within a single
broadcast domain. If you specify a "/112" network size, the "5" and "6"
in your addresses are NOT different subnets within the space; they are
the upper part of a 16-bit host number within the IPv6 network.
Bruce A. Hudson				| Bruce.Hudson at Dal.CA
ITS, Networks and Systems		|
Dalhousie University			|
Halifax, Nova Scotia, Canada		| (902) 494-3405

More information about the dhcp-users mailing list