192.168.2.33/24 & 192.168.2.33/29 on the same box

192.168.2.33/24 & 192.168.2.33/29 on the same box

[lejeczek]

hi everybody

I'm hoping an expert could help me, clarify this one for me, 
should be simple I guess, probably not for a newbie like me

having on one system

physical eth 192.168.2.33/24
and a
bridge (only taps no phys) 192.168.2.33/29

I cannot get to anything behind 192.168.2.33/29 from 
anything behind 192.168.2.33/24 (and vice versa)
each side can get respectively tofurther-out interface of 
the 192.168.2.33
routing + forwarding I have it set up all I believe

is such a configuration even valid? should be, right?

I'm trying to understand subnet concept of, in this case 
class C private net - is 192.168.2.33/29 still a part of 
192.168.2.33/24 or it is a whole separate network.

regards
P.

Re: 192.168.2.33/24 & 192.168.2.33/29 on the same box

[/dev/rob0]

On Mon, Apr 07, 2014 at 12:58:00PM +0100, lejeczek wrote:
> I'm hoping an expert could help me, clarify this one for me, should 
> be simple I guess, probably not for a newbie like me
> 
> having on one system
> 
> physical eth 192.168.2.33/24
> and a
> bridge (only taps no phys) 192.168.2.33/29

When you're going to bridge an interface, you assign it "0.0.0.0/0" 
(which is to bring it up.) Then you assign an IP address to the 
bridge.

No time to look it up for you right now, but I believe the brctl(8) 
manual should cover this.

> I cannot get to anything behind 192.168.2.33/29 from anything 
> behind 192.168.2.33/24 (and vice versa)

Broken bridge, I guess.

> each side can get respectively tofurther-out interface of the 
> 192.168.2.33 routing + forwarding I have it set up all I believe
> 
> is such a configuration even valid? should be, right?
>
> I'm trying to understand subnet concept of, in this case class C

Do yourself a favor: totally forget about "class".

> private net - is 192.168.2.33/29 still a part of 192.168.2.33/24
> or it is a whole separate network.

It is indeed a part. To turn those addresses into valid CIDR 
expressions, change the last quads to be the network address:

1. 192.168.2.33/29 becomes 192.168.2.32/29
   This includes IP addresses 192.168.2.32 through .39
2. 192.168.2.33/24 becomes 192.168.2.0/24
   This includes IP addresses 192.168.2.0 through .255
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