broadcast adress assignement in GUI

[Vram]

On Thu, 2006-01-26 at 11:11 +0100, Gaël Varoquaux wrote:
>     Hi,
> 
> 	sorry if this isn't the right place to discuss this, but I think
> my issue is related to the gnome-system-tools package which refers to
> this mailing list.
> 
>     My remark is the following : consider a network with the following
> settings in the "Network settings" GUI :
> 
>     address 10.10.156.13
>     netmask 255.255.0.0
>     gateway 10.10.156.1



For my $$..  

You are using a class A address space with a class  B mask /16

Therefore  you network number is 

10.10.0.0

Your broadcast is 

10.10.255.255

HTH 

Vram

> 
> 	Now I do not know that much about networks, but I think this
> means that I can speak to 10.10.159.14 without going through the gateway.
> 
>     Now suppose their is a windows server on 10.10.159.14 . A lot of
> communication with the windows server is done through broadcast
> messages. However if I set through the GUI these settings, my broadcast
> will be set to 10.10.156.255 (am I wrong ?). Therefore I won't see the
> windows server, and I won't appear on its "workgroup" list, even if my
> samba server is properly configure. This is not a theoretical scenario,
> I ran into this problem at work today. I edited the
> /etc/network/interfaces and solved it, but I am not satisfied by this
> solution : it is not easy to find out the problem and a newbie will
> simply not solve it without help.
> 
>     I suggest that either there is a broadcast field added to the GUI,
> or, perhaps better, the the GUI tries to guess the broadcast address
> with the netmask (I don't know if this is possible).
> 
>     I am interested in your comments on this. If you think this is a
> good idea, this should go upstream to the developers of the program, as
> this can be a rather insolvable issue for the newbie who doesn't even
> know that there might be a broadcast address to play with.
> 
>     Regards,
> 
> 	Gaël
>