was bogon filters, now "Brief Segue on 1918"

Joel Jaeggli joelja at bogus.com
Wed Aug 6 11:36:05 CDT 2008


Darden, Patrick S. wrote:
> Most organizations that would be doing this would not randomly pick out subnets, if I understand you.  They would randomly pick out a subnet, then they would sub-subnet that based on a scheme.  I believe this is the intent of RFC 1918.  Not to apply a random IP scheme, but to randomly pick a network from the appropriate sized Private Networking ranges, then apply a well thought out scheme to the section of IP addresses you chose.
> 
> E.g. 10.150.x.y/16 as their network.  X could be physical positioning, and Y could be purposive in nature.  10.150.0.0 as basement, 10.150.1.0 as first floor, 10.150.2.0 as second floor, etc.  1-20 as switches/routers, 21-50 as servers and static workstations, 51-100 as printers, and 101--200 as DHCP scope for PCs, and 201-254 for remote login DHCP scope (vpn, dialup, etc.)
> 
> Yes, I think a large private network would work this way.  RFC 1918 wants it to work this way (imho).

How much of 10/8 and 172.16/12 does an organization with ~80k employees, 
on 5 continents, with hundreds of extranet connections to partners and 
suppliers in addition to numerous aquistions and the occasional 
subsidiary who also use 10/8 and 172.16/12 use?

> --p
> 
> -----Original Message-----
> From: Joel Jaeggli [mailto:joelja at bogus.com]
> Sent: Wednesday, August 06, 2008 11:21 AM
> To: Darden, Patrick S.
> Cc: nanog at nanog.org
> Subject: Re: was bogon filters, now "Brief Segue on 1918"
> 
> 
> Darden, Patrick S. wrote:
>>    *randomly* from the reserved pool of private addresses, when
> 
> You're supposed to choose ula-v6 /48 prefixs randomly as well... Any 
> bets on whether that routinely happens?
> 
> While you're home can probably randomly allocate subnets out of a /8 or 
> /12 for a while without collisions, nobody that's actually building a 
> subnetting plan for a large private network is going to be able to get 
> away with that in v4.
> 





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