Re: ADSL

["alcinababe" <alcinababe@xxxxxxx>]

--- In ukha_d@xxxxxxx, Simon Kennedy <stonewolfsoft@y...> wrote:

> So what is the benefit of a router AND IPCop on a
> dedicated PC (hardware firewall)? Some, none at all?

IPCop *is* a router (amongst other things).

=20
> Can someone describe what the router part actually
> does. From product descriptions on the web it seems a
> router is

A router 'routes' signals.  That's all (actually it's a minor miracle
*how* it does it to my mind!).  For example, it takes a request for a
web page from one of your computers, and passes it onto the modem and
thence onto the www.  It then takes a request from a different
computer on your network, and passes that on too.  The clever bit is
that it *remembers* which computer asked for which page, and when the
answer comes back directs the page to the correct computer!  Clever
eh?  The usual protocol that is used to do that is NAT.


> ADSL modem + NAT + DHCP + Firewall
>=20
> Which bit of the above is the router part or is it
> something that is missing.

NAT.  Um....Network Address Translation I think.  The modem part turns
a phone signal into a computer signal.  The DHCP part dynamically (ie.
when you switch your computer on) allocates IP addresses to your
computers.  The Firewall trys to prevent nefarious script kiddies from
accessing your computer network whilst at the same time allowing you
legitimate access.  The NAT part does the clever bit described above.


> Part of my problem is there seems to be the usual
> computer problem of a blurring of terms. You look on
> the web for an ADSL modem and what you get is an ADSL
> router with modem or you look for an ADSL router and
> what you get is the router part only.

The problem as I see it is that these boxes are sold under the name of
"adsl router".  But they usually contain much more than just a
router!
"adsl router" appears to be used as a generic term for one of
these
boxes, not to be confused with "router" by itself which is
something
quite specific!


> Another question has just occurred to me. How can you
> have an ADSL router without the ADSL modem part? Isn't
> that just a router?

Um...yes!  Originally you had to buy your modem from BT and they were
very picky about you trying to use anything other than the prescribed
adsl modem.  Consequently you only needed a router, not a router +
modem.  Things have changed now.


> I am currently assuming that an IPCop PC will handle
> all the routing/NAT etc.

Yup.  And the DHCP.  And the Firewall.  And the Dynamic DNS.


> There seems to be a large overlap between what the
> router provides and what IPCop provides but I'm not
> sure if the parts where it doesn't overlap are
> critical.

Yup.  Basically the "adsl router" is a single self-contained
black
box, which is intrinsically silent (no fan) and which can be easily
rebooted by just unplugging and replugging.  IPCop is a piece of
software (ok...it's a piece of software and an operating system) which
you install on an old PC which has been dedicated for that express
purpose.  That PC may well have a fan (ie. it will be noisier than the
black box) and requires a little more attention to reboot it.=20
However...and this is where opinion as to which is better gets
divided..IPCop is upgradable to plug up any new holes that are
discovered in it, whereas a black box is a black box and few are
upgradable should a hole be found in their security.

Personally I run IPCop.  I do this because it cost me nothing (old
computer being chucked out) whereas the black box would have cost me
=A3100.  Pure and simple.  =A3100 versus =A30.  (I already had the modem
>from

HOpe this helps
Alcina