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cable modem question/help please

macstudent

macstudent

macrumors 6502
Original poster
Feb 12, 2002
436
1
Milwaukee, WI
Hi, I just had a cable modem installed today at our house.

here is the problem. IT was installed on a pc by the cableguy, and now I want to get on the net with my ibook 700 512mb ram osx10.1.5.

Anyway, I uplugged the ethernet cord from the back of the pc and plugged it into the ibook. Unfortunetly the ibook is not recognizing the connection. I have used it before in computer labs at school and I have done the same thing at my parents house (switching the ethernet cord). I don't know why this is not working.

My only thought is that when the cable guy set it up on the pc he did something to prevent the signal to work with any other computers. (i really am stumped)

thanks in advance.
 
Your ISP may need the mac address of the NIC in your iBook added to their database so that the cable network DHCP server will allow you to have an IP.
 
Easy fix

I have had the same problem, but there is a simple answer.

(I will explain as best as I understand it, and I know there are other specific and technical terms that I can use, but I kept it simple -- so don't comment on my verbaige... please)

When the cable modem boots up, it registers with the ISP and registers the connected PC. Once it has that information, it works just fine. But if you change the PC after it has been registered, then it won't work because it no longer matches the dynamic settings that it had when it started. The PC also has to get the IP address in the DHCP settings.

Solution:
-- Connect the iBook to the cable modem, via Ethernet.
-- Reboot the cable modem
-- Power up the iBook if it isn't up already
-- Done

The longterm, Alternate Solution is to get a router and a switch (or hub, but I don't recommend them).

I have a cable modem connected to Airport2, which is my Router. An Ethernet cable coming from the Airport2 to a Switch and two WinTels connected to the switch. A third machine, the new iMac, is wirelessly connected downstairs.

I can connect whatever computers I want, dynamically, and it automatically connects it to the internet.

You see, the router acts like the computer when the cable modem is booted up, and as far as the ISP is concerned, you only have on machine connected (the Router). It registers once, it is the Router that then gives you additional IP addresses dynamically as you connect the computers to the switch.

Sorry if this was too much info., but I got mine working well and I'm just sharing what I did.

Take care,
Quark
 
The above may also work, it all really depends on how your ISP runs the DHCP servers and how they keep them secure (e.g. the mac address filtering).
Best bet is to give them a call yourself and ask.
 
Quark and verbose101 are right

Quark is right. What he sugests should work. You sould get a router. You can pick one up with a built-in 4port switch for like $50. Then you can hook up up to 255 computers to your same cable line. Run DHCP on your router (most have a DHCP server on them) and you can just plug and play network connections all day long. I have a linksys Wireless routher w/4 port switch. It works great.

verbose101 is right, the mac address is sometimes registered with your ISP and/or your Cable modem. But it is extreamly expensive and fairly simple to spoof a mac address. As a packet is sent and routed through a network, it picks up macaddresses at all the routers and managment switches it passes through. It would be a nightmare to trace a point to point mac address. Some routers will even let you give it a mac address.

Restarting your modem should work. If your modem is like mine, you need to powerit off for at least a few seconds to let the cash clear before you reboot it.

-evildead
 
Re: Quark and verbose101 are right

Originally posted by evildead
You sould get a router. You can pick one up with a built-in 4port switch for like $50.
Click to expand...

damn they're 100$ over here >_<
 
If you buy a cheap router, you are getting a cheap router. Spend the few extra dollars to get a good one. From everything I have seen and heard, Linksys appears to be the one to go with. While some people have success with DLink and others, it appears to be more of a hit or miss situation with them. Linksys does support the Mac with their routers, and you can update the firmware from a Mac as well.

Spend a few extra $$ now, and save the money that you would spend on the brews to relieve the stress that follows the cheaper routers.
 
Agree with AlphaTech

I recommend that you get a router/switch with a built-in firewall - a little extra security goes a long way. Some of them have a DMZ if you need to have a machine in the clear to support hosting games or a website. I have a NetGear RF114, cost about $115 over a year ago, works great. One feature to look for of course is a minimum 10/100 Mbs hub, makes the LAN work a little faster for Macs:D
 
I forgot to mention Netgear in my previous post. I have an eight port switch at home, connected to my Airport base station and it has been working flawlessly for more then a few years now. I would consider getting one of their routers, if I ever needed one. I don't, since the new base station has a firewall integrated into it.
 
I have a Linksys 4 port router with a built in switch. It lets me share files between an imac and a G4, and it lets them both be on the internet at the same time. I did used to do the unplug/plug in other machine thing, but I had to restart the modem each time. It really pissed me off, so I just got the router. The model number is: BEFSR41 V.2
It is a $100(U.S.) router, but I got it on sale for $65.:cool:
 
The linksys is a good router. At I saw it on sale at bustBuy for $50... thats the one I was talking about when I mentioned a $50 router.


-evildead
 
Originally posted by AlphaTech
I just checked Best Buy's web page and the only ~$50 Linksys item that have is a 5-port switch. The 4-Port Cable/DSL Router is ~$90.
Click to expand...
Ya, dont forget that it has to be a router. A router and a switch are not the same thing. dont make the same mistake that I did.:D I bought a switch thinking that it was the same thing as a router. Whoops
 
Originally posted by AlphaTech
I just checked Best Buy's web page and the only ~$50 Linksys item that have is a 5-port switch. The 4-Port Cable/DSL Router is ~$90.
Click to expand...


It was a few weeks ago when I saw the sale. Sorry, I forgot to mention that. When I saw It I told a buddy of mine and he went out and grabbed it right away. I paied $200 for my wireless one and I have seen it for $140.. I guess thats the way it goes.

-evildead
 
Here's my setup!

I have a cable modem thats hooked up to a Xsense Router, then it hooks up to my little 5 port ethernet hub, then the wires lead to my Macs and PCs... :)
 
Thanks for all the helpful info. I had the same problem with my iBook and iMac and now I can easily swap the ethernet cable between them and, voila, both computers on the net (not simultaneously, though)

I would like to point out one small thing...

if you read the fine print on your cable contract, I'm sure you see that (in most cases) your ISP specifically prohibits the end user from running a DHCP server using that connection (i.e. they dont want you to share your connection. They want you to purchase multiple IPs!)

Anyway, I just think its a little odd that software piracy discussions dont go over very well on these boards, but discussions about how to "share" your internet connection is perfectly OK!?!?

Please disregard this if, in your area, connection sharing is allowed. With my ISP (Rogers here in Canada), it is certainly not. Now, that hasnt stopped me from...oops, better stop right there!
 
Re: Here's my setup!

Originally posted by LimeiBook86
I have a cable modem thats hooked up to a Xsense Router, then it hooks up to my little 5 port ethernet hub, then the wires lead to my Macs and PCs... :)
Click to expand...

Switches are better then hubs... With hubs, you divide the speed by the number of systems/devices on it, and then take 1/2 of that. With a switch, you get full bandwidth to the device you are going to (like a server/another computer or printer). Switches are full duplex, while most hubs are 1/2 duplex. The duplex indicates if you get full speed or not over the network in each direction (100Mb/s up and down). With a 5-port hub, the most you will see for network speed (to other computers on the network) is 25Mb/s (if you only have one computer you are connecting to) in each direction. With a switch, you can have 100 devices on the network (each on it's own network switch connection) and you will get 100Mb/s in each direction.

For anyone that hates bottlenecks, the ONLY way to go is with a switch. :D
 
Well, Edge100, I don't know about you guys up in Canada :p, but down here it's not prohibited to put more then one system onto your high speed internet connection.

Most ISP's won't officially offer support for more then one unless you get their networking package, but that doesn't stop their tech's from helping you out anyway. I have found that to be true of Earthlink DSL down here in MA...
 
AlphaTech,

I stand corrected. Up here, we sign a gigantic contract that basically says we wont run any kind of server whatsoever (web, ftp, file sharing, DHCP, POP, etc.). My ISP has a program that allows you to purchase extra IPs from them, although, as you say, they will not support the physical networking of the two computers, only the connection.

Its funny, though. Here I was walking around thinking everyone suffered from the same restrictions as me:eek:

Well then...keep on sharing your connections...legally.
 
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