ADSL connection qustion

On Wed, 17 Dec 2003 02:45:18 -0000, "Justin"
<(E-Mail Removed)> wrote:

>Hi everyone!
>
>I am going to build a network to share broadband internet at home, its going
>to look like:
>
>Internet ----------- ADSL Modem --- Router/Firewall ---Switch --- LAN
>computers
> (Ethernet)
>
>(i dono if I should have hardware router or an old 486 linux router yet)

What do you mean by a "hardware router"?

>These ADSL providers are saying their connection is always on, so I take it
>that means static IP

You may have the same ip address for a long time but it can be changed
without you knowing. So in reality it is not static.

> but as i havnt actually got it yet I dont know if
>"always on" actually means that, and if the modem will always automatically
>maintain the connection by itself and dont need something to tell it to
>connect.

An isp that states "always-on" means that they monitor your circuit.
If for any reason there is a disconnection then you will be
reconfigured (perhaps with a different address and different dns
servers). So the intelligence of "always-on" rests with the isp and
not with the user (or "inside the modem"). Note that this is simply
for configuration purposes. You can still configure yourself via
clientside software (such as ppp). I am not sure what happens if a
client initiated connection goes down.

Justin wrote:
> Hi everyone!
>
> I am going to build a network to share broadband internet at home, its going
> to look like:
>
> Internet ----------- ADSL Modem --- Router/Firewall ---Switch --- LAN
> computers
> (Ethernet)
>
> (i dono if I should have hardware router or an old 486 linux router yet)
>
As long as your 486 can push ~384Kb/sec of data (avg. dsl rate), then
your ADSL line will be your bottleneck. I'd just use the 486 with some
extra ram chunked in if you have it laying about.

> These ADSL providers are saying their connection is always on, so I take it
> that means static IP etc,
No. Always on is usually their marketing term for a low/no latency
connection. As opposed to a dial up service, where you actually need to
dial the ISP phone number, the ADSL modem can forward your LAN traffic
shortly after power on with little or no intervention from any machines
that you place on your network. However, it does not mean staic IP
addresses. Usually, ISP's will provide DHCP services from the C.O., or
from a DHCP server running on the DSL modem.


> "always on" actually means that, and if the modem will always automatically
> maintain the connection by itself and dont need something to tell it to
> connect.
Typically, although some ISPs use the term "always-on" as a synonym for
DSL, or broadband internet access. They may still assume that you will
run a pppoe or simmilar client on one of your host machines. these
clients can be configured to start automatically in the backround when
your system boots, giving the appearance of an "always-on" connection.



But I'm worried that if the "always on" connection somehow goes down,
> how am I going to tell it to connect from one of the LAN computers (assuming
> the modem doesnt auto reconnect)?
If your ADSL connection, goes down, then what alternative do you have
for getting to the internet? Besides, if the connection goes flickers
and the modem doesn't re-negotiate, all you really need to do is power
cycle the modem, not the router.

> given these circumstances is a hardware router going to be a better choice?
Nope. Its not going to help above and beyond the PC alternative.

HTH
Neil



--
Neil Horman
Red Hat, Inc., http://people.redhat.com/nhorman
gpg keyid: 1024D / 0x92A74FA1, http://www.keyserver.net

Neil Horman wrote:
> Justin wrote:
>
>> Hi everyone!
>>
>> I am going to build a network to share broadband internet at home, its
>> going
>> to look like:
>>
>> Internet ----------- ADSL Modem --- Router/Firewall ---Switch --- LAN
>> computers
>> (Ethernet)
>>
>> (i dono if I should have hardware router or an old 486 linux router yet)
>>
> As long as your 486 can push ~384Kb/sec of data (avg. dsl rate), then
> your ADSL line will be your bottleneck. I'd just use the 486 with some
> extra ram chunked in if you have it laying about.
>
>> These ADSL providers are saying their connection is always on, so I
>> take it
>> that means static IP etc,
>
> No. Always on is usually their marketing term for a low/no latency
> connection. As opposed to a dial up service, where you actually need to
> dial the ISP phone number, the ADSL modem can forward your LAN traffic
> shortly after power on with little or no intervention from any machines
> that you place on your network. However, it does not mean staic IP
> addresses. Usually, ISP's will provide DHCP services from the C.O., or
> from a DHCP server running on the DSL modem.
>
>
>> "always on" actually means that, and if the modem will always
>> automatically
>> maintain the connection by itself and dont need something to tell it to
>> connect.
>
> Typically, although some ISPs use the term "always-on" as a synonym for
> DSL, or broadband internet access. They may still assume that you will
> run a pppoe or simmilar client on one of your host machines. these
> clients can be configured to start automatically in the backround when
> your system boots, giving the appearance of an "always-on" connection.
>
>
>
> But I'm worried that if the "always on" connection somehow goes down,
>
>> how am I going to tell it to connect from one of the LAN computers
>> (assuming
>> the modem doesnt auto reconnect)?
>
> If your ADSL connection, goes down, then what alternative do you have
> for getting to the internet? Besides, if the connection goes flickers
> and the modem doesn't re-negotiate, all you really need to do is power
> cycle the modem, not the router.
>
>> given these circumstances is a hardware router going to be a better
>> choice?
>
> Nope. Its not going to help above and beyond the PC alternative.
>
> HTH
> Neil
>
>
>
Well, one thing to think about is the electricity bill.

Mike

"Justin" <(E-Mail Removed)> wrote in message
news:brlrl5$gpa$(E-Mail Removed)...
> Hi everyone!
>
> I am going to build a network to share broadband internet at home, its
going
> to look like:
>
> Internet ----------- ADSL Modem --- Router/Firewall ---Switch --- LAN
> computers
>
>
> (i dono if I should have hardware router or an old 486 linux router yet)

>
> These ADSL providers are saying their connection is always on, so I take
it
> that means static IP etc,

No it might not be a static ip address . They only mean to say that they
dont time your connection, they have no rules saying you must disconnected
after N hours connected or X minutes idle and you can never get locked out
because the server is busy.


> but as i havnt actually got it yet I dont know if
> "always on" actually means that, and if the modem will always
automatically
> maintain the connection by itself and dont need something to tell it to
> connect.

Modems do not maintain connections. Routers do.



> I would like to build the linux router myself, it'll be a very interesting
> task. But I'm worried that if the "always on" connection somehow goes
down,
> how am I going to tell it to connect from one of the LAN computers



Well, if the ISP had problems, the linux system should just keep retrying.
If you have a hardware router, it will just keep retrying to connect.


>(assuming
> the modem doesnt auto reconnect)? I wouldnt be home for weeks at a time to
> type anything in the CLI! My family dont know a thing about linux or
> routers, and in any case the linux router is going to be headless,
> keyboardless etc, I dont want them to blindly mess around in linux.

Same problem with a hardware router,
and same problem for connecting a PC straight to the modem.

If they connect their PC straight to the line and they use Windows - well
windows can get itself messed up much more often and in many more ways than
a linux box.


The hardware router doesnt get "messed up", rebooting it will bring back the
stored configuration.


> given these circumstances is a hardware router going to be a better
choice?

Yeah, you can get cheap combined ADSL modem, router firewall devices.

These can be cheaper than paying for the ISP's modem.

If you ISP "gives" you the modem, then you are paying for it through a long
contract, or something.

Eg my ISP wanted Aus $170 for their modem, but I bought a billion
modem/router/firewall for Aus $190. I bought the expensive model, the
billion 5100 would be Aus $100

Hi everyone!

I am going to build a network to share broadband internet at home, its going
to look like:

Internet ----------- ADSL Modem --- Router/Firewall ---Switch --- LAN
computers
(Ethernet)

(i dono if I should have hardware router or an old 486 linux router yet)

These ADSL providers are saying their connection is always on, so I take it
that means static IP etc, but as i havnt actually got it yet I dont know if
"always on" actually means that, and if the modem will always automatically
maintain the connection by itself and dont need something to tell it to
connect.

I would like to build the linux router myself, it'll be a very interesting
task. But I'm worried that if the "always on" connection somehow goes down,
how am I going to tell it to connect from one of the LAN computers (assuming
the modem doesnt auto reconnect)? I wouldnt be home for weeks at a time to
type anything in the CLI! My family dont know a thing about linux or
routers, and in any case the linux router is going to be headless,
keyboardless etc, I dont want them to blindly mess around in linux.

given these circumstances is a hardware router going to be a better choice?

Anything from ppl in the know would be extremely helpful!!!

Thanks in advance

"Justin" <(E-Mail Removed)> wrote in message
news:brof0p$br5$1@

>However, it does not mean staic IP addresses.

thats correct.

> Usually, ISP's will provide DHCP services from the C.O., or
> from a DHCP server running on the DSL modem.

Thats very misleading and confused compared to reality. Forget it.
He didnt say this sentence.

DHCP at the client side is up to the client, the ISP has no say.
How the ISP allocates IP addresses is up to it, dont worry about it.

Modems dont do anything like this, routers do. But theres the silly hybrid
things which are between modems and routers, just treat them like a modem
and forget how they actually do it, it wont help you to think about this
hybrids.



> I think i had the wrong idea about ADSL connections, from what you said,
an
> ADSL connection is unlike a dial up connection, once I power up my ADSL
> modem the connection is made.

No its just like a modem call. The modems at each end negotiate to talk to
each other, then there is a authentication phase and then they exchange Ip
addresses ... just like PPP over phone modems.


> modem to do that obviously, so how I can get the linux router to do that
for
> the whole LAN automatically everytime authentication is required? (you
> mentioned pppoe, will that do this job?)

yes, the PPPoE client uses the modem , as ppp uses a v90 phone modem.
The Internet IP address appears on an interface on the linux box. The linux
box then can contact the internet, and you can then set up the firewall as
nat/masquerade, and/or set up proxy servers.

>and is it possible to use any of
> the LAN computers to authenticate through the router?

PPPoE talks to the modem via ETHERNET addresses, so there is no simple way
for this to occur.

Linux doesnt route Ethernet, it routes tcp/ip.

You could set up the linux box for bridging and then it would allow PPPoE to
work between a PC on the LAN and the modem. but then the ISP also needs to
allow this, you need a seperate login, and most ISPs dont want to give you
multiple login accounts.


Routers/Firewall hardware run PPP, they can be configured to stay connected,
or connect on demand. but basically the ISP is happy for you to stay logged
in , it doesnt consume any resources!

Justin wrote:
> "Neil Horman" wrote in message
>
>
>> As opposed to a dial up service, where you actually need to
>> dial the ISP phone number, the ADSL modem can forward your LAN traffic
>>shortly after power on with little or no intervention from any machines
>>that you place on your network. However, it does not mean staic IP
>>addresses. Usually, ISP's will provide DHCP services from the C.O., or
>>from a DHCP server running on the DSL modem.
>
>
> I think i had the wrong idea about ADSL connections, from what you said, an
> ADSL connection is unlike a dial up connection, once I power up my ADSL
> modem the connection is made.
In some cases, it really depends on what your ISP has configured.
> but I think my ISP requires username/passwd
> authentication before I can actually use the connection,
Thats pretty likely.

> I cant get the
> modem to do that obviously,
Thats not always true. I've got an acatel modem on which I can specify
user name and password lists to use for automatic authentication via
pppoe on ADSL lines
> so how I can get the linux router to do that for
> the whole LAN automatically everytime authentication is required?
Most pppoe packages have an associated scripting language that let you
script actions to take in response to certain events. You'll need to
read the man page for your pppoe package (assuming your provider users
pppoe..it sounds like they do).


> you mentioned pppoe, will that do this job?)
Yep.


> the LAN computers to authenticate through the router?
Not that I'm aware of, although with the right equipment, you may be
able so set things up so that in the event your router fails, you could
circumvent it and establish a pppoe session with individual clients on
your internal network.



--
Neil Horman
Red Hat, Inc., http://people.redhat.com/nhorman
gpg keyid: 1024D / 0x92A74FA1, http://www.keyserver.net

Leon. wrote:
> "Justin" <(E-Mail Removed)> wrote in message
> news:brof0p$br5$1@
>
>
>>However, it does not mean staic IP addresses.
>
>
> thats correct.
>
>
>> Usually, ISP's will provide DHCP services from the C.O., or
>> from a DHCP server running on the DSL modem.
>
>
> Thats very misleading and confused compared to reality. Forget it.
> He didnt say this sentence.
>
Actually is quite accurate. There are local ISPs here which provide
ADSL/broadband modem/routers which incorporate dhcp services expressly
for the purpose of allowing multiple client machines at the customer end.

> DHCP at the client side is up to the client, the ISP has no say.
> How the ISP allocates IP addresses is up to it, dont worry about it.
>
DHCP at the client side _can_ be up to the client, but many ISP's
provide the service in the modem, either statically serving private
network addresses (192.x or 10.x, etc.), or via dhcp relay from the CO.

> Modems dont do anything like this, routers do. But theres the silly hybrid
> things which are between modems and routers, just treat them like a modem
> and forget how they actually do it, it wont help you to think about this
> hybrids.
>
God forbid he should understand what components reside in a piece of
technology. Just because its commonly called a modem, doesn't mean it
strictly conforms to the more traditional definition of the term. And
routers don't provide DHCP either, DHCP servers do. ADSL/broadband
modems just commonly incorporate DHCP/router and modem services.



--
Neil Horman
Red Hat, Inc., http://people.redhat.com/nhorman
gpg keyid: 1024D / 0x92A74FA1, http://www.keyserver.net

On Wed, 17 Dec 2003 09:49:53 -0500, Neil Horman
<(E-Mail Removed)> wrote:

>Leon. wrote:
>> "Justin" <(E-Mail Removed)> wrote in message
>> news:brof0p$br5$1@
>>
>>
>>>However, it does not mean staic IP addresses.
>>
>>
>> thats correct.
>>
>>
>>> Usually, ISP's will provide DHCP services from the C.O., or
>>> from a DHCP server running on the DSL modem.
>>
>>
>> Thats very misleading and confused compared to reality. Forget it.
>> He didnt say this sentence.
>>
>Actually is quite accurate. There are local ISPs here which provide
>ADSL/broadband modem/routers which incorporate dhcp services expressly
>for the purpose of allowing multiple client machines at the customer end.

It looks to me that we are confusing terms such as "client" meaning
customer or as being a DHCP client and whether a DHCP server is the
entity that provides a live internet address or one that provides
internal addresses to LAN hosts.

A DHCP server that provides live internet addresses cannot be
incorporated in any device residing with the customer. I think that
is what Leon meant to say.

>> DHCP at the client side is up to the client, the ISP has no say.
>> How the ISP allocates IP addresses is up to it, dont worry about it.
>>
>DHCP at the client side _can_ be up to the client, but many ISP's
>provide the service in the modem, either statically serving private
>network addresses (192.x or 10.x, etc.), or via dhcp relay from the CO.

As far as DHCP client, Leon meant that it is up to the customer device
(router, modem, host, etc) to enable such a thing (i.e. to request an
internet address).

>> Modems dont do anything like this, routers do. But theres the silly hybrid
>> things which are between modems and routers, just treat them like a modem
>> and forget how they actually do it, it wont help you to think about this
>> hybrids.
>>
>God forbid he should understand what components reside in a piece of
>technology. Just because its commonly called a modem, doesn't mean it
>strictly conforms to the more traditional definition of the term.

It is very useful for a beginner to understand traditional methods
than to try to understand networking using modern devices which
incorporate multiple features/concepts.

>And
>routers don't provide DHCP either, DHCP servers do. ADSL/broadband
>modems just commonly incorporate DHCP/router and modem services.

Well look who is falling back to traditional methods now? A modern
router does indeed provide DHCP "features" or "services" such as a
"DHCP server" (for LAN hosts) or a DHCP client (to receive an external
address). So to say that a modern home router does not provide "DHCP"
is either too vague or an exercise in splitting hairs.

On Thu, 18 Dec 2003 02:28:18 -0000, "Justin"
<(E-Mail Removed)> wrote:

>
>"Neil Horman" wrote in message
>
>> As opposed to a dial up service, where you actually need to
>> dial the ISP phone number, the ADSL modem can forward your LAN traffic
>> shortly after power on with little or no intervention from any machines
>> that you place on your network. However, it does not mean staic IP
>> addresses. Usually, ISP's will provide DHCP services from the C.O., or
>> from a DHCP server running on the DSL modem.
>
>I think i had the wrong idea about ADSL connections, from what you said, an
>ADSL connection is unlike a dial up connection, once I power up my ADSL
>modem the connection is made. but I think my ISP requires username/passwd
>authentication before I can actually use the connection,

The principle is the same as dial-up. You always need two things:

(a) account authentication (username/password)
- this can be achieved via a router
- or an internet gateway/firewall
(b) configuration of your routing device.
- If you have a modem that acts as a router then this is what
gets configured.
- If you have a host (behind a traditional adsl modem) acting
as a firewall then this is what gets configured

>I cant get the
>modem to do that obviously, so how I can get the linux router to do that for
>the whole LAN automatically everytime authentication is required? (you
>mentioned pppoe, will that do this job?)

The authentication device (see above) willl provide this feature
through network address translation (NAT, or ip masquerading).

PPPoE itself is a networking protocol only. It is a fairly recent
method in North America (2 years I believe) for communicating to one's
ISP with a broadband modem (xDSL, cable, wireless). See RFC2516 for
details:

http://www.faqs.org/rfcs/rfc2516.html

>and is it possible to use any of
>the LAN computers to authenticate through the router?

Again, only one device authenticates. And it does this once. If you
disconnect then you must authenticate again. This device can then act
as an internet gateway for multiple lan hosts. Of course, these lan
hosts must be configured correctly (in particular, to use the internet
gateway's internal network adapter as a host's default routing
gateway).