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Tuesday, September 1st, 2015 8:00 PM

ipv6 multiple subnets?

I am trying to wrap my head around IPv6 and how I might be able to use it (I don't care about it being publicly accessible, just usable by every host on my LAN across multiple networks). I also don't care that it isn't static, if comcast changes it on me, I will just adapt with it. I am mainly interested in working with it to learn it's behavior.


I have an SMC D3G, and it is configured for "Both" (stateful/stateless). It also shows a /64, and any device I connect directly to the modem receives a working IPv6 configuration from this /64.


If I want to introduce router separated networks (using linux routers in my case), how is this typically done with and an assigned IPv6-PD?


I know IPv6 requires some new thinking, so I am open to being wrong, but I believe I am correct in believing that introducing a router would require a new subnet, a new /64, and static routes each way?


I keep reading that /64s are generally the smallest subnet you should assign, but all I am seeing is the single /64 in the UI. I am also reading some posts that say business customers receive a /56, if this is true, is there a way to figure that out? Or do I have to call in to check?


I guess any feedback while I tinker around would be helpful, thanks.



Problem solver


117 Messages

9 years ago

There is little you can do with a vendor-supplied router except wait for possible updates to appear. So the baseline configuration for you to manage your local subnet addressing is to place the vendor router in bridge (passthru) mode so that your local router can receive the /56 Prefix Delegation and do the appropriate magic.


So your solution has two parts, Part 1 of which may be performed iteratively as your knowledge grows:


Part 1: Configure your local router to

  • Accept the IPv6 assigned WAN address
  • Accept the IPv6 delegated /56 prefix
  • Assign local LAN /64 prefixes
  • Record in detail how you accomplished this

Part 2: Convince your vendor to configure the vendor router to bridge mode

  • Request the configuration change
  • Verify the configuration change
  • Connect your local router and verify proper operation
  • Record in detail how you accomplished this.

The most important steps above are the "Record in detail" steps to aid you when things get broken. They will.