> On Feb 11, 2015, at 4:51 AM, Julian Elischer <jul...@freebsd.org> wrote:
> 
>> On 2/11/15 5:55 PM, Matt Churchyard wrote:
>> 
>> I appreciate that it might be 'valid' as a binary mask, but I'm struggling 
>> to find any documentation anywhere that actually suggests that it's valid as 
>> a network configuration. The entire modern CIDR notation, and all the 
>> routing system & hardware built around it (that shows networks in CIDR form 
>> and will collapse routes) has no way of dealing with these subnets.
> most can deal with it, just not optimally
>> 
>> Are there actually valid use cases for these types of network?
> yes.
> I've had networks that were the first and last quarter of a /24, and the 
> middle two quarters were separate nets.
> 
> Sure, it made my skin crawl, but I was in a pinch to get more machines onto 
> that /26.
> all four were served by the same router so only one router needed to know..
> 
> I have however at times though we could think about making ifconfig at give a 
> warning.
> (but not an error).

https://lists.freebsd.org/pipermail/freebsd-hackers/2011-April/034997.html
Subject came up on -hackers in 2011

Quoting RFC-1219:

"While RFC-950 allows the "ones" in the subnet mask to be non-contiguous, 
RFC-950 recommends that 1) they be contiguous, and 2) that they occupy the most 
significant bits of the "host" part of the internet address."

Jim
_______________________________________________
freebsd-net@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-net
To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"

Reply via email to