Text 12564, 80 rader
Skriven 2010-11-24 17:05:00 av Peter Knapper (3:772/1.0)
  Kommentar till text 12538 av Michiel van der Vlist (2:280/5555)
Ärende: N'other one evicted from dyndns?
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Hi Michiel,

 MvdV>  MvdV>> What is the point of a home router if the 
 MvdV> only thing connected to
 MvdV>  MvdV>> it is that one computer?

 PK> A valid question, but a perfectly valid answer 
 PK> is that it can assist
 PK> to offload certain processing from the computer

 MvdV> Computers have so much power these days, that I do 
 MvdV> not think this is an issue for that user with one 
 MvdV> computer.

However I was not thinking of processing power, rather reducing complexity by
removing the WAN interface requirement from the Computer. This means that just
about any computer can be dropped in place of the original with no (or minimal)
Networking changes required. With a fixed Host doing the WAN interfacing, this
would add (IMHO) complexity to that one computer.

 PK> AND it allows me to place certain criteria on that connection,
 PK> external to the machine in question, without the need to modify the
 PK> Machine in question.

 MvdV> Makes sense if you have more than one machine. Makes 
 MvdV> less sense if you have only one.

Even with one it makes perfect sense to me, as it allows me to place a barrier
between the Public world and the Private world. That extra Barrier adds
complexity to the task of breaking it for the hacker. Of course nothing is ever
permanently resolved in this setup, as new issues are found almost daily.
However these "issues" are most likely protocol specific.

If just one machine is managing that Barier, then I have to be pretty confident
on getting it exactly right, and I have worked in the Professional Networking
area for long enough to know that even purpose built devices can still have
bugs. One only has to search the Cisco Database on fixed issues to find out
about these...


 PK> But the finer points of doing this are probably 
 PK> something you consider unimportant...

 MvdV> Not at all, I consider it very important. It is just 
 MvdV> that I get the impression that many think that a 
 MvdV> router with NAT is essential for connecting to the 
 MvdV> internet. While in fact NAT is a kludge needed 
 MvdV> because ISPs will only give one IPv4 address to 
 MvdV> private customers.

I do not consider NAT a Kludge at all, however it IS an added "work-around" to
the limited IP Address space issue with IPV4, PLUS it is used heavily to
enhance protection to Private environments that need Public access.

 MvdV> Also many seem to think that NAT is a safety feature. It is not.

NAT by defaut does add a (thin) layer of "safety" (IMHO), however like most of
TCP/IP, one realy does need to know what one is doing, before one allows such a
setup loose in Public...

 MvdV> (*1) It may be that only 29 are available for the 
 MvdV> user. If what you get is actually a /27 subnet, than 
 MvdV> the one with the last five bits set to zero is the 
 MvdV> subnet address, the one with the last five bits set 
 MvdV> to one is the broadcast address and the modem istself 
 MvdV> will also take one address. But I am not sure if it 
 MvdV> works that way, and I have no way to check. Nor the 
 MvdV> need, as I will never get 32 IPv4 addresses from my 
 MvdV> ISP.

You are right, using conventional Network design, however here in NZ, with
ADSL, (normally implemented as PPPoA) most Private Homes connect using a /32
mask and have jsut 1 Public IP address, and certain "work-arounds" are handled
by the ISP to allow things to work without a separate Broadcast address and
Network address.

Cheers..............pk.

--- Maximus/2 3.01
 * Origin: === Maxie BBS.  Ak, NZ +64 9 444-0989 === (3:772/1)