Re: Multi-Networking in Linux - Multiple Subnets

On 31/07/2026 07:15, Marc Haber wrote:
> Since then people using the
> "class X" terminology only divulge their outdated knowledge.
> 
> Greetings

And you are merely demonstrating that whilst you know one little 
factoid, you are fucking ignorant about much else.

The  internet at large went classless because the BGP routers could 
handle the table sizes involved.

The class ABC terminology persisted as a neat way to refer to specific 
netmasks

And the private networkls of those sizes were defined to never be on a 
public network or routable by BGP

In the end its the usual mix of pedantry, technical issues and common 
speech.

https://datatracker.ietf.org/doc/html/rfc1918

RFC 1918 may be 30 years old, but it is still in effect. And it refers 
to classful networks


In a private network you can do WTF you like and have network spaces at 
any one bit boundary of a netmask . You can probably create even weirder 
netmasks than 2^n -1 boundaries, though only Farley Flud would try one.

Most people stick to the simple cases. And split into 'class C sized' 
subnets even in larger corporations because it limits the extent of 
broadcast floods. Even though switches already limit traffic between 
nodes to that which is desired only.

Carlos has a point. If Starlink restrict his router to a precise local 
IP and netmask, if he wants more he has no real option than to create 
some routable subnet .


-- 
“Ideas are inherently conservative. They yield not to the attack of 
other ideas but to the massive onslaught of circumstance"

    -  John K Galbraith