routing - method

Currently I have a 56k modem feeding a small network, both wired and
wireless.

For internet access a Linux machine connects and using NAT my other
computers can access the internet via my Linux connection (I find this
easier than via Windows).

Many enthisiasts I speak with tend to favour a Linux machine acting as
a server rather than MS

I will soon be getting broadband and am wondering, if I get a
broadband router how is this routed, does the router have a mini OS
installed.

Geoff Lane

Geoff Lane wrote:
> I will soon be getting broadband and am wondering, if I get a
> broadband router how is this routed, does the router have a mini OS
> installed.

Yes - essentially a router is just a specialised computer. It may have a
hardware OS (on ROM) or may have some form of storage that can be
upgraded. Large routers from Cisco (the only ones I knew until getting a
broadband router) tend to have a compact flash card with Cisco's
Internet Operating System loaded onto it.

Your BB router will have a connection to the external line, and will
terminate on the internal side with either a single Ethernet port (mine
takes address 192.168.7.1 on the private address range) or may have an
integrated hub or switch. In the latter case, the router will still have
an IP address, but it will be as if it were attached to an invisible
port on teh hub/switch. You can run the network off this device
(abandoning the Linux router) or connect the device to your existing
Linux router and make the Linux box act as a firewall as extra
protection behind the BB router. This way the Linux device can also do
your network services like DHCP, which I find easier to set up on a
Linux box than my BB router.

Other people with more home-context routers will no doubt be able to
supply more information )

- Iain.

--
Please remove the obvious subdomain to reply.

On Wed, 10 Sep 2003 17:13:15 +0100, Geoff Lane <(E-Mail Removed)>
wrote:

>Currently I have a 56k modem feeding a small network, both wired and
>wireless.
>
>For internet access a Linux machine connects and using NAT my other
>computers can access the internet via my Linux connection (I find this
>easier than via Windows).
>
>Many enthisiasts I speak with tend to favour a Linux machine acting as
>a server rather than MS
>
>I will soon be getting broadband and am wondering, if I get a
>broadband router how is this routed, does the router have a mini OS
>installed.

Yes, they do have their own OS, usually held in eeprom / flash to
allow it to be upgraded easily; Many of them allow you to set up
static routes, or to use RIP 1 or 2 to communicate routing information
to other computers connected to the local network.
(This is how my network is currently set up; About the only piece of
routing set up I needed to do was to define a default gateway for the
server.)

One thing you'll find with Linux is that it doesn't use standard
routing syntax, meaning that if you're used to setting up routing with
Linux, routing information on other OS's may look a little odd until
you get used to it, and vice versa.

Derek
--
"Mine's the anorak on the left. Oh... they're all anoraks?"

On Wed, 10 Sep 2003 18:09:42 +0100, Iain Hallam
<(E-Mail Removed)> wrote:


>> I will soon be getting broadband and am wondering, if I get a
>> broadband router how is this routed, does the router have a mini OS
>> installed.
>
>Yes - essentially a router is just a specialised computer.

>You can run the network off this device
>(abandoning the Linux router) or connect the device to your existing
>Linux router and make the Linux box act as a firewall as extra
>protection behind the BB router. This way the Linux device can also do
>your network services like DHCP, which I find easier to set up on a
>Linux box than my BB router.

Hm, it seems I will have more options open to me.

I'm not too au faix with the Linux OS though learning well, it seems
easier to use with Internet sharing so I generally connect with that.
It has a very simple firewall (IP tables) set up.

My Windows boxes each run their own version of ZoneAlarm and I have a
handheld device that has no protection of its own but currently is not
a target for hackers.

I'll definitely get a router to leave my options open.

Thanks for the good explanation.

Geoff Lane

During a perfect moment of peace at Wed, 10 Sep 2003 17:13:15 +0100,
Geoff Lane <(E-Mail Removed)> interrupted with:

>I will soon be getting broadband and am wondering, if I get a
>broadband router how is this routed, does the router have a mini OS
>installed.

The router is just a cut down version of commercial routers. They have
firmware that understand the necessary aDSL protocols, IP and can
route between two interfaces. Don't expect the router to even
understand RIP V1, it doesn't have to.

Geoff Lane wrote:
>
> Currently I have a 56k modem feeding a small network, both wired and
> wireless.
>
> For internet access a Linux machine connects and using NAT my other
> computers can access the internet via my Linux connection (I find this
> easier than via Windows).

It's certainly more flexible and reliable. I find it easier too but this
is probably because I am much more familiar with Linux than Windows.

> Many enthisiasts I speak with tend to favour a Linux machine acting as
> a server rather than MS
>
> I will soon be getting broadband and am wondering, if I get a
> broadband router how is this routed, does the router have a mini OS
> installed.

As others have stated, the router does indeed have an OS, even if it is
on a ROM. It is a very specialised minimal one as you surmise.

Is this ADSL or cable? With ADSL it's certainly advisable to get a
router as the reports I have seen from people playing with PPPoA on
Linux are not encouraging. It works but clearly isn't simple. Cable is a
lot easier, it's just a straightforward ethernet presentation with DHCP.

So my 2p worth is:

If it's ADSL, get a single port router and put your Linux router behind
it. With iptables you can build a much more effective and flexible NAT
firewall than the router will manage. There is no difficulty with
running two levels of NAT; NAT is transparent so the second one doesn't
know about the first IYSWIM;

If it's cable, don't bother with the router, just use your Linux
machine.

I have cable (NTL) and am using an old laptop running OpenBSD as the
router. Linux with a 2.4 kernel and iptables will be just as effective.
Don't use anything earlier, the ipchains firewall in 2.2 is not stateful
and nowhere near as good.

Regards, Ian

On Wed, 10 Sep 2003 23:02:50 +0100, Ian Northeast
<(E-Mail Removed)> wrote:

>> I will soon be getting broadband and am wondering, if I get a
>> broadband router how is this routed, does the router have a mini OS
>> installed.
>
>As others have stated, the router does indeed have an OS, even if it is
>on a ROM. It is a very specialised minimal one as you surmise.
>
>Is this ADSL or cable?

ADSL

>With ADSL it's certainly advisable to get a
>router as the reports I have seen from people playing with PPPoA on
>Linux are not encouraging.

I think a router is favourite with me at the moment,

>If it's ADSL, get a single port router and put your Linux router behind
>it.

The only thing I'm not too crazy on is having to leave the Linux box
on to have access by the other machines.

>With iptables you can build a much more effective and flexible NAT
>firewall than the router will manage.

That is a definite plus point.

>There is no difficulty with
>running two levels of NAT; NAT is transparent so the second one doesn't
>know about the first IYSWIM;

That's interesting.

Thanks for the info.

Geoff Lane
Welwyn Hatfield Computer Club - Hertfordshire, UK
www.whcc.co.uk - Online facilities for non locals