Home Networking with a One Way Cable Modem?
Blacklotuz asks: "I recently networked the computers in my house with a Linksys EtherFast Cable/DSL Router. Today I called up Comcast to order cable internet service, but because I live in a rural area we still have downstream only cable. I was told that in order to use the service I would have to connect the cable modem to the ethernet card on my computer as well as dialing up via the 56k modem. Im running Windows XP on the computer that will be dialing up. Does anyone know of a way to use a one way cable connection with a router?"
How much is ComCast charging you for such a brain-dead service?
And are you actually going to pay for it?
yeah... use full-duplex satellite instead... all you need is a view of the southern sky...
When I had a similar one way service ages ago, I had a cable modem with a DB9 port for an external modem. Worked well, though I'm not sure what standard it used since it was wireless. You may want to check around for a different cable modem with this option.
Does anyone know of a way to use a one way cable connection with a router?
A one-way cablemodem is a router. If you want to hook up another one, hook it up. Anything more requires you telling us why exactly you're trying to hook up a router in the first place.
Providers are starting to roll out DOCSIS 1.1 systems now, and DOCSIS 2.0 is only a few months out, if you believe CableLabs. Even so, most cable systems should be supporting high-bandwidth symmetric tiered service by next year.
Where exactly do you live?
"Anything is better than IE, and you can quote me on that." -- Wil Wheaton.
Why would you need a router? If you only have one machine, then you are set to go without a router.
If you have two machines, then you have two options as I see it. First (1) is to use the XP box to proxy the I-Net connection out to your other box, or (2) set a third computer up to do that for you. Any machine that has a routing table like the one that they are asking you to setup will be robust enough to handle any day-to-day routing that you might be talking about.
If that doesn't answer you question then, I guess you want a black box router that you can run through. All I can say is "My condolences to your dreams". After a cursory look over the web I have found plenty of routers with Ethernet/serial ports, but the thing is they use them as separate ports, and you want to use them as a MUX of sorts. If you got a cisco2500 (?) then you might be able to route all outbound traffic to one side of the box, and allow inbound traffic to run in from anywhere.
I'm not so sure that this would allow you to make and maintain a connection to your dialup ISP, but it may make your dreams come true. Also note that compared to my earlier solution, this one would be VERY VERY expensive.
Plug the Linksys into the cable modem. Plug the computer into the Linksys. Plug the phone line into your computer. The Linksys should be transparent to you. It should be opaque to the rest of the world.
If tits were wings it'd be flying around.
I have the same situation setup right now through RCN. I likewise live in a back-asswards area with only one-way service. The cable modem connects directly to the modem through a standard modem cable. The cable modem than plugs into the Linksys router which plugs into the hub.
you might be able to use a linux server to do this. i'm not sure if it would work, but here's the idea:
that should give you the single bi-directional interface to plug into your router. you might also try
i don't know enough about bonding to say whether this would work or not, can anyone help me out here?
Somewhere on this page I have hidden my signature.
Not to be a troll, but I think you should consider yourself to be lucky to receive cable television at all in a rural area. I live just two miles outside of a town of about 500, yet I do not have access to public water, waste, garbage, gas, or cable services. My electricity comes from a rural co-op, which thankfully, is quite cheap. Telephone is similar, though my local calling area is worthless... about the only folks I can call local is a town of about 250 that's about 20 miles to the east of me. I can't even call the nearby town nor the nearby city locally.
But that's about the end of my rant. I wouldn't give it up for anything. The trees, the quiet, the river, the lake. "We're from the country and we like it that way". And because of my consulting business I can afford a T1 from Sprintlink.
Why not simply set up one of your machines as the router. Hook the internet into it. THen hook that into your network, since I assume right now your only using the switch part of the linksys box anyway. THis will turn the main machine into a router. If you want to be able to dial out from any machine in the network, you could use something like VNC or pcanywhere. You can then sell the linksys box and just get a switch, using the money for other things. Windows XP makes all of the networking INSANLY easy. Just run Network Setup Wizard.
Sig!
Why does distance have anything to do with it ? If you can receive data one way, then why can't you send data the other way ? The physical link is there, it might be a little laggy compared to a downtown setup but should still work, no ? Especially since cable uploads are always capped at a fraction of the downstream, things should work just fine, but without hogging a phone line.
Cable bound to a 56k really defeats the purpose, since a big selling point of cable is that it's "always on", just fire up a browser and let it rip. If you have to go back to the dark ages of phone dialing, then it ain't worth squat. Get ISDN instead.
-Billco, Fnarg.com
To use NAT though, both the upstream and the downstream must be connected to the same routing device. An old computer would do the job nicely.
A good friend of mine had the very same situation, upstream-only cable modem. The cable modem that he was provided with, however, did the dialing, NOT his PC. He instantly was able to use a broadband (LinkSys actually) router. Look into that possibility.
Motorola and 3com both sell cable modems specifically engineered for your situation. Sell or return your existing box and buy one. Your TV cable and the modem link will plug into one box, which will in turn connect via ethernet to a single PC, or to a cheap ethernet hub (or switch) which can then be connected to multiple PCs.
If you'd rather do it the hard way, get an old PC from the recycling bin (or some corporate dumpster) and run linux/IPtables or OpenBSD/packetfilter and use gated to manage the routing. The PC will be your router/firewall.
If you choose the second option, you are going to retain the linksys, so be sure to get the latest firmware download for it because those things are notoriously crackable. If you choose the first, be careful with the ethernet side of the cabling - you will need a different cable (a crossover or hub-to-hub cable) from a cable modemhub or switch than you would from the cable modemPC.
It's not hard. First challange is to get your happy little linux box using the cable modem on its own. The problem is that some distributions (and most sets of firewall rules) disable having a request go out one interface and the reply come back on another. There's a setting somehwhere under /proc to allow that traffic, but I don't have access to my boxen right now so I can't look it up.
What the cable company is doing is assigning you a static dialup address and then associating that address with the cable modem's MAC. This allows you to call out, but inbound traffic is routed to your cable modem. As far as the internet is concerned, your IP address is the one on your PPP interface.
Once all that is working, standard NAT implementations should work fine. The IP-Masquerade HOWTO is a fine place to start. Keeping in mind that your external interface is your PPP adapter, NOT the ethernet to the cable modem.
This sort of thing may or may not work with Windows intert connection sharing.
1-way cable? Forgivable.
Dumb questions about routing? Everyone has to learn at least once. Forgivable.
Using a linksys router? Retarded.
Seriously, short of buying a catalyst 5000, nothing beats a linux (or BSD, I suppose) box. Got that old weird vintage computer with only an arcnet nic? A linux router/firewall will put that on the net too. 1 way cable modem? Linux supports modems and ethernet. Want to do something fancy? Linux can do almost all of it. Firewall rules need to be a bit more complex (which yours will be) ? It can do that too.
A linksys costs money better spent buying some 10/100 nics, a switch, junk food, hookers... nearly anything, you name it. It can't do a single thing I've listed above. Some things are beyond your control (being stuck in the boondocks), but others are flat-out, no excuses possible, mistakes. Correct them quickly, and then return for some useful answers...
Well, if you don't need any security, linux with IP Masq works perfectly fine with my One-Way satellite internet /w modem uplink. Why wouldn't that work for your cable modem?
Just open everything up and close it all down until you're happy (and things still work).
So you're free to use any router you want.
Okay... I'll do the stupid things first, then you shy people follow.
[Zappa]
A Catalyst 5000 is a switching solution, not a routing solution. A layer 2 device, not layer 3.
It only becomes a layer-3 capable device if you add an RSM Blade (Route Switch Module), or an NFFC (NetFlow Feature Card).
Other than the Cisco gaffe, I'm with you. Linux makes a great router/firewall, and should be able to handle this task. It almost makes me wish my cable-modem had been a one-way system to begin with so I'd had a chance to solve this problem.
Without the ability to test, I'd imagine that the solution lies in having a 3 interface system, 2 ethernet cards, and 1 modem for PPP.
Establish the PPP connection, assign the IP address to the Inside ethernet, and bridge between the outside ethernet (connected to the cable modem) and the inside ethernet.
A multi-homed Linux-box or Router should not care that the return traffic comes in on a different interface than it was sent out over... After all, it has to be able to handle diverse paths, as it cannot dictate the return path from the remote system.
You'd just make certain that your default route pointed out the PPP interface, Masquerading the stations as it went.
I'm sure there's a gotcha in there somewhere, or someone else would probably have done this, but that's where I'd start.
So excuse me, it's about the only cisco product I know by name.
You're going to see problems in iptables, I think. I've never had an opportunity to play with a situation like that though. Seen several options in the kernel config for it, and in theory I know it should work. I'm confident I could get it to work myself, after twiddling awhile. But rather than him asking an intelligent question that I might have been compelled to research a bit for the answer, we get this mindless linksys drivel. God, there are some things I wish would never have been sold.
LinkSys, and it's equivalents (D-link, blah, blah, blah), fill a role. Not everyone is going to become a Unix or Network guru, and for that I am eternally greatful. That way, the rest of us can eek out a living by working impossible feats of magic, taking payment in the coin of the realm.
God bless the unwashed masses!
It's nice that you imply that I'm included in the "us can eek out a living by working impossible feats of magic" but the truth of the matter is I'm unemployed. As far as that goes, I've never been able to find a job where they trust me with much more than unboxing the new Dells/IBMs and setting them up on the desk.
I think it's possibly because I'm an ijit.
Further proof: My only router is a cruddy Bay Networks I got at auction for $5. Can't even play with it, because there is only one ethernet interface... the other 2 are some weird serial ports with plugs I can't find anywhere. Oh well. If God had wanted me to be blessed with Cisco hardware, I would have been born in a dumpster in San Jose.
Well, enough of the self-pity... it's time to install OS/2 v1.3 ! I think I have the perfect PS/2 286 for it, and it's time to fill out the token ring segment (so far, only a Mac Quadra 605 and the dual p100 linux server are on token ring). Plus, I've got a assembly language tutorial I've been promising to finish for spalp.org for 3 months...
Zebra is an open source multi-protocol routing software developed to run on Unix systems (actually developed on Linux). It utilizes a *very* IOS-like command structure, and supports RIPv1/2, OSPF, and BGP. It also supports the IPv6 specs for each of those protocols.
It is close enough to IOS to be useful from a training and functionality standpoint.
I haven't messed with it in about 18 months, but it was good back then. I'm sure that it's even better today.
Check it out.