was bogon filters, now "Brief Segue on 1918"

Darden, Patrick S. darden at armc.org
Wed Aug 6 11:26:51 CDT 2008

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. as basement, as first floor, 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).


-----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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