Re: Proper Broadcast Address ?

[Jay Daniels <jay infoave net>]

On Sat, 2002-06-29 at 07:21, Emmanuel Seyman wrote:
> On Sat, Jun 29, 2002 at 06:42:16AM -0400, Jay Daniels wrote:
> > 
> > Setup a couple of DSLs on Linux using a subnet mask of 255.255.255.224
> > and I am concerned about the "broadcast" address. This is the only value
> > that the technician did not supply.
> 
> Here's how I do it.
> The first IP address of your network is reserved (it's the network address).
> The last IP address is also reserved (it's the boardcast address).
> Everything between these is yours to use.
> 
> Your subnet mast is 255.255.255.224 .
> In binary, this translates to : 11111111 11111111 11111111 11100000
> 
> This means that you have a range of 32 IP addresses, the last one 
> of which is the boardcast address.
> 
> HTH.
> 
> Emmanuel
> 

I see. But actually I have only one IP alloted me and those 32 addresses
on the subnet belong to the isp's other dsl customers on the same
subnet???

Also, I am assuming (after reading the Linux DSL howto) I am on a
bridged DSL network - the howto says you cannot tell...  

There also does not seem to be any type of authentication.  Is this
correct, or is it using my old dialup values in /etc/ppp/???-secrets? 
All I did was run ifconfig on each nic and setup the ip, ip mask,
gateway address, etc on a base Redhat Server install, and it all started
working.  

"In fact, I had the Linux box up before the technician had his Windows
XP Laptop configured to do the test!"

What type of security risk are involved on this type of network besides 
someone else DoS my box and getting my ip?  Which would be obvious since
I could not connect.

I am new to dsl and everything works now, I but would like to learn
/how/ this particular setup works without breaking it.



jay