RE: ipv6 - NAT-PT

From: ccie2be (ccie2be@nyc.rr.com)
Date: Mon Apr 25 2005 - 13:46:09 GMT-3

Bob,

I should also probably stay away from any clear non-water liquids.

Thankfully, some people know to speak verrry slooooooowly when I get this
way.

Thanks

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Bob
Sinclair
Sent: Monday, April 25, 2005 11:48 AM
To: ccie2be; 'Group Study'
Subject: Re: ipv6 - NAT-PT

Tim,

 I am sure this is a momentary lapse on your part! Please put any sharp
objects out of reach before proceeding!

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################

Would you agree that, say, 172.16.10.0/24 is carved from (a subnet of)
172.16.0.0/16?? Aren't subnets of longer mask length than their parents?

Re advertising the nat prefix /96: RIPng or OSPF v3 should do the job
nicely

HTH,

Bob Sinclair
CCIE #10427, CCSI 30427, CISSP
www.netmasterclass.net

  ----- Original Message -----
  From: ccie2be
  To: 'Bob Sinclair' ; 'Group Study'
  Sent: Monday, April 25, 2005 11:43 AM
  Subject: RE: ipv6 - NAT-PT

  Hey Bob,

  Yes, I have that book and I checked to see if it shed anymore light on
these
  questions prior to my posting on GS.

  Unfortunately, that book didn't have anymore info about this than what was
  in the Cisco doc.

  But, I fully agree with you about that Cisco Press book - a must read for
  all current ccie candidates.

  Getting back to this issue of the nat /96 prefix - how is a /96 prefix
  "carved" from a /64 bit address?

  I could understand how that would work in reserve i.e. carving a /64
prefix
  from a /96 prefix.

  And, also, if there's no requirement for the interface ipv6 address to be
  related to the nat prefix, how would that prefix be advertised?

  Thanks for getting back to me.

  Tim

    _____

  From: Bob Sinclair [mailto:bsin@cox.net]
  Sent: Monday, April 25, 2005 11:30 AM
  To: ccie2be; Group Study
  Subject: Re: ipv6 - NAT-PT

  Hi Tim,

  Per my experience, the ipv6 nat prefix does not necessarily match any
  portion of the interface addresses. I suspect the example assumes one
would
  carve one's /96 nat prefix from one's assigned /64 space. You are
  certainly on the right track re the necessity to advertise the /96 nat
  prefix to other routers. Have you seen the Regi Desmeules IPV6 book from
  Cisco Press? Definitely a must have, IMHO.

  HTH,

  Bob Sinclair
  CCIE #10427, CCSI 30427, CISSP
  www.netmasterclass.net
  ----- Original Message -----
  From: ccie2be <mailto:ccie2be@nyc.rr.com>
  To: Group Study <mailto:ccielab@groupstudy.com>
  Sent: Monday, April 25, 2005 10:55 AM
  Subject: ipv6 - NAT-PT

  Hi guys,

  I've been going over the Cisco doc's on this

 
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/ipv
6
  _c/sa_natpt.htm

  and it seems to me there are a lot of conceptual blanks that need to be
  filled in.

  I'm hoping with the help of GS to be able to fill-in those blanks.

  If you look at page 338 from the above link, you'll see that a portion of
  the ipv6 address assigned to the interface matches the ipv6 nat prefix
  defined in step 3.

  My guess is that is required but the doc doesn't say so. Is that
required?
  Also, notice that only the first 8 hex digits of the ipv6 address match
the
  ipv6 nat prefix.

  Why only the first 8 hex digits?

  Also, I assume that some IGP must be used to advertise the ipv6 nat prefix
  although none of the examples show this. My reasoning is this: If the
  other ipv6 routers don't know where the nat-pt router is, they can't send
  packets to it. I also assume that the reason the interface has an ipv6
  address that partially matches the ipv6 nat prefix is so that when an IGP
is
  configured on that interface, then the other ipv6 routers will know how to
  reach the nat-pt router.

  Is that assumption correct?

  I'm doing my best to try to fill-in the blanks but I'm completely guessing
  about all these things.

  Can someone explain what's really going on with this and if I'm on the
right
  track?

  TIA, Tim

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