[lug] cable modem network topology

Mr Viggy LittleViggy at alum.manhattan.edu
Sun Jul 21 00:30:34 MDT 2002

Dude, it sounds to me like all you really need is a simple bridge. 
Can't you set a bridge up to allow clients on one side to request IP 
addys from the other side?


D. Stimits wrote:
> Barney Treadway wrote:
>> FWIW...
>> Our office runs on a single cable connect coming in through a RCA cable
>> modem that drops into a cheapie Lynksys router (<$100). Macs, Linux, 
>> M$ all
>> live happily behind it. The little config tool for the Linksys is very 
>> easy,
>> open ports where you want em, set up the dhcp etc however you want. 
>> Can even
>> get the wireless + 4 port for about $130 or so.
> I am avoiding wireless, I don't like the security, and probably even 
> worse, latency. I already have a good 8 port switch and several network 
> cards, even some Fast Cat 5 cable (though probably not enough). However, 
> the idea of a single unit that routes for multiple DHCP clients does 
> intrigue me. My question is whether it does this through some form of 
> proxy/NAT/masquerade, or if it leaves all units fully visible on all 
> ports (desired for a few quirky apps that need the outside to come in 
> for contact)? Is it possible to add a Linux firewall in there with this, 
> even with something like 3 DHCP machines acting independently (which is 
> why the bridging filter has been a hot topic for me)? If this thing is 
> configurable for firewalling, and does all the DHCP bridging/routing, it 
> just might be a good idea.
> D. Stimits, stimits @ idcomm.com
>> With the "always on" we never lose our IP, except when they lose it 
>> for us.
>> B
>> ----- Original Message -----
>> From: "D. Stimits" <stimits at idcomm.com>
>> To: <lug at lug.boulder.co.us>
>> Sent: Saturday, July 20, 2002 3:46 PM
>> Subject: Re: [lug] cable modem network topology
>>> Terry Branaman wrote:
>>>> On Fri, 2002-07-19 at 18:23, D. Stimits wrote:
>>>>> That reminds me, does anyone know if the AT&T cable comes with choices
>>>>> on cable modems? If so, are there good/bad choices here? I assume
>>>>> external is best, but I read in one FAQ already that at least one 
>>>>> cable
>>>>> modem is PNP set to require the o/s be PNP-aware. Now if the modem is
>>>>> rented ($2/month), I wonder how they feel about running a utility 
>>>>> to set
>>>>> it to non-PNP-aware.
>>>> When I signed up, the rent was more like $10/month or higher, so I went
>>>> out and bought a Toshiba cable modem. I just looked for a modem that 
>>>> has
>>>> the certification that they require (as listed on their web site). 
>>>> It is
>>>> external, and has a 10-base T port, so it plugs in to the NIC in my
>>>> firewall machine, which is using Linux. I just had to set up networking
>>>> to use their DHCP server, since they won't assign static IP addresses.
>>> I'm looking more closely at their advertisements, and comparing to what
>>> the guy told me on the phone. It looks like you are right about this,
>>> and maybe it is even as high as $15/month charge. There is mention that
>>> you are allowed to purchase your modem either directly from AT&T, or
>>> else buy it elsewhere. I am thinking of looking around to see what
>>> stores have, if any are available. Do any of the local retail stores
>>> actually sell cable modems? I would think it is a product available only
>>> online, but I kind of wanted to look at the boxes. I don't imagine many
>>> people in Boulder use cable modems, since DSL is so popular there. But
>>> by the time you include the cost of the phone line itself, the cable
>>> modem seems far cheaper. I am beginning to like the idea of a bridge (or
>>> backup idea from Sean, proxy ARP) on cable modem better and better (to
>>> tell the truth, I kind of have fun setting up this sort of thing, so
>>> long as there is no schedule that says I have to work 24/7 to meet a
>>> deadline). My guess for local retailers that sell cable modems would be
>>> CompUSA, but almost nobody else (Circuit City?). I will shop online, but
>>> if anyone knows of stores that have such products in stock where I can
>>> walk in and look at the box, give me a shout.
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