HELP! iMac, cable modem won't go. [Archive]

stripes

21-02-2007, 11:35

No, the G3 IS going okay.

I have the machines side by side. If I connect the ethernet cable to the G3, power down the modem, repower, switch all on again, G3 works fine.

If I do the same thing to the iMac, no go. I get a constant '169...' address, rather than the proper ntl IP connection.

Last night, I left the modem completely switched off for 20 hours - co-axial out, ethernet out, power out. Turned it on today and same as before, i.e. won't connect to internet.

Could it be that the ntl central system is somehow LOCKED on to my old G3, in some way that the twenty hour switch-off wouldn't cure? NTL claim this is impossible, and won't even talk about the possibility.

What I didn't tell you originally was that last week the iMac was brand new, and had these problems. I convinced Apple that the machine was faulty (having been convinced by the service personnel at ntl), so Apple sent me a SECOND brand new iMac. Same problem. NTL still say it can't be at their end, and Apple, quite understandably, think they've done all they can, barring the almost total impossibility of them supplying two brand new machines each with the same ethernet problem.

Me? I am in despair, as no-one will take responsibility, and I have now spent hours and hours, quite literally, to the Apple Support centre, and to the ntl support line, and have got, precisely, nowhere.

Anyone who can offer a solution will have my undying gratitude!

Allen.

Chris

21-02-2007, 11:44

Have you cross-referenced all your system preference settings between the two Macs to ensure the new one is set up correctly?

Did you by any chance use Migration Assistant to copy data and apps from the old iMac to the new one?

It's hard to say what the problem is without having the full facts. It could be something as simple as not having DHCP set in the new iMac for receiving the IP address.

stripes

21-02-2007, 12:37

handyman

21-02-2007, 12:42

work, I shall be round to my local Maplin before you can say Internet...

Be careful with maplin, some of their stuff can be very expensive and not as current as other places. To be fair you'll get a good deal on linkys or belkin routers from pc world or dixons (currys digital). They have wireless routers on offer at Ãƒâ€šÃ‚Â£40 from time to time.

Chris

21-02-2007, 13:00

Hello Chris T.

Not completely sure what you mean by cross-referencing. We (Apple and me) have tried connecting using 'ordinary' DHCP, and occasionally manual DHCP (where we did enter various IP, router, etc., addresses), all with no success.

The G3 is OS8.6, the iMac is OS10.4 (Intel), so the way they are set up is only similar, not the same.

No, I didn't use Migration Asst. on setting up the iMac. All I did was turn it on. There is a point in the turning on process where the Mac tries to connect to the internet to register; that was the point (with each iMac) where the message 'unable to connect to the internet' came up.

The iMac, typically of Macs, hasn't got much in the way of setting up. Basically all you do is go to System Preferences, make sure Built-in Ethernet is chosen, even deselect the other options like Airport to make sure they don't interfere, make sure 'DHCP' is chosen rather than the other options (manual DHCP, for example) and that SHOULD be that.

Just a notion (something one of the Apple guys mentioned). Would it be worth me getting a router to plug into the modem, the purpose of which would be (hopefully) that the incoming signal would only care about the modem and router, not what was connected to it. Or is that just another forty quid down the drain? If there is the FAINTEST chance that this would work, I shall be round to my local Maplin before you can say Internet...

Thanks for your interest.

Allen.

Aah, sorry, I hadn't appreciated that you had been persisting with quite such an elderly iMac for so long. Congratulations for keeping on going with OS 8! I'm not certain that the Migration Assistant would work for you anyway, if you don't have a version of OS X on your old machine. Never mind, it was just a thought and shouldn't prevent you from getting the right settings into your new machine anyway.

The iMac should indeed do as you describe. I have set two of them up on my home wireless network and never even needed them to be plugged into my router at any stage. Both immediately detected my wireless network and, as the network is unsecured (very rural and isolated so minimum risk) they just got online straight away.

I think it highly unlikely that two different iMacs would be supplied to you with faulty ethernet hardware so I don't think the fault is in the computer. If you have System Prefs set to use Ethernet, with automatic DHCP, that is all you should need. Either your modem is on the way out - unlikely, as it still consistently works with your old iMac - or, and this is the only alternative I can think of, the network is not wanting to register your new MAC address. In this instance, power-cycling the modem should fix the problem. I notice you have tried that already but you do need to give it more than a few seconds so trying it overnight will be worthwhile.

stripes

21-02-2007, 13:55

Hello ChrisT, and thanks for those ideas.

(In fact the elderly machine is a 1997 G3 but doesn't affect your conclusions).

I tried powering down for twenty (yes 20) hours, yesterday afternoon to today, with no change, so that probably rules out the power-down as a solution.

Various threads on the Apple Store discussion forums show quite a few other iMac/cable modem problems, with the super-fast Intel iMac being allegedly too advanced for the old bog-standard modems. But on the other hand there are thousands of iMac users out there connected happily to the www, so I don't think it's inherent in the iMac.

Solutions in the States have been varied, including buying new cable modems (not an option here in the UK), slowing down the ethernet speed on the Imac, etc. The router solution hasn't been suggested, or rather I can't find it, but there are hundreds of messages, so a bit difficult.

How about this router idea? Is there any logic to it, i.e. does the ntl signal come rattling down the line, into the modem, find its way blocked by a router, and give up rejecting my iMac? Or is this just fanciful.

I'm fairly laid back about the problem, now, as a) I am old, and therefore have a degree of patience, b) it WILL be solved, sometime, and c) not being connected to the Internet isn't the same as having your leg sawn off (believe me, I know about that one).

However, the flat is tiny, and I really would like to give away the G3 (if I can find any takers) and concentrate on playing with my shiney iMac.

Thanks again, and further ideas still DESPERATELY welcomed.

Allen.

maverick

21-02-2007, 14:08

The cable modem your using is it an Ambit model you can tell if it has got rdy and sync lights.
If it is then unscrew the coaxial cable from it,reboot the mac and re check the ip address,let us know what ip appears,reconnect the coaxial cable reboot modem and the mac and again recheck the ip.

melevittfl

21-02-2007, 14:13

OK,

On the cable modem, there should be a light labeled "Enet". When you plug the ethernet cable into the iMac, that light should light up.

If it doesn't then your iMac and your cable modem aren't making a physical connection. Before buying a router, try a new ethernet cable.

If the light does come on, that your iMac is making a physical connection, then, can you please open the Applications folder, then open the Utilities folder and run the Terminal application. You'll see a black screen with a command-line prompt. Type "ifconfig" (without the quotes) and press enter. If you could, please copy and paste the output so we can see it.

Thanks,
Mark

bayonet

21-02-2007, 14:17

As maverick says when you disconnect the coax the IP should be 192.168.100.x didn't I see you had that somewhere earlier but if it connects to the old MAC it should connect ok to the new one

I don't get a lot of calls with MACs just plug 'em in and away to go

Set Network to Automatic built in enet and assigned by DHCP they usually pick up an IP address no problem no fuss

I'm sure the MAC bods on here will advise even better than someone who has a limited knowledge of them like me. They don't give much problem on routers either

ShadowTD

21-02-2007, 14:58

melevittfl

21-02-2007, 23:22

Again, the first thing to check is that the Enet light on the cable modem is on.

Stuart

22-02-2007, 00:02

This is tres odd.

Thanks to other posters for clearing up the MAC address points. I would maybe suggest that at this point you try to get a new cable modem out of Ntl, as yours really seems to have a problem. The new Intel Macs use standard Intel chipsets these days, so it's not just a 'Mac thing'.

However, if there are documented Cable Modem/Mac Ethernet problems you could always buy a router from Argos and take it back if it doesn't solve the problem - god bless that 14 day Money Back Guarentee!

It's worth noting that the Macs have always followed international standards for Ethernet. As should all devices attached via Ethernet (NTL modem included).

One thing that can cause a problem though. When you connect a device to Ethernet, there are several speeds it can operate at. Therefore, each device has to try different speeds to see which the other can use. This is called "Auto Negotation".

Now, not sure if you can do this on the mac (sadly, I'm at home, and don't have access to a Mac to try) but it might be possible to force your mac to use either 10 or 100 Mbit.

stripes

22-02-2007, 08:43

Right, thanks for all those.

I'm connected through the G3 at the moment.

Modem is an 'ntl 250'. Sync and Ready come on. Enet comes on. Disconnecting coaxial changes nothing. IP address under all test conditions comes back as 169...

Just looking at ifconfig. Yes, got to that stage, Mark, but I haven't got any physical connection between the two machines, so can't copy and paste. I know it's very difficult doing this from a distance, but can you tell me what I'm looking for (or rather what YOU'RE looking for)?

Stuart: I have changed the speed (tip from the Apple Discussion message board) but still 169...
You can choose speeds of 10, 100, or 1000.
You can choose half-duplex, full-duplex, or full-duplex flow-control.
You can choose Maximum Packet Size either 1500, or 9000, or custom, range 72-9000.
I tried the low figures in all cases, with half-duplex, then full-duplex. All came back to 169 (and yes, I did reboot iMac and modem each time).

Shadow: I asked NTL for a new modem. I even offered (this is how desperate I am) to PAY for a new modem from them. Point-blank refusal. 'If the modem is working on the G3, then there's nothing wrong with it.' They did send an engineer out early on in the saga, who didn't know much, but who stuck a meter on the modem and said the signal was okay. That was as much as he knew about modems.

I spotted the Apple-recommended router (Belkin 4-way) on Amazon's 'used' list, and as it was only twenty-five quid have ordered it. At least it'll eliminate that area.

So, thanks again for your help, and at the moment I'm pinning my hopes on that router, on the basis that the signal will recognise the modem, then hopefully the router, then my G3, and won't trouble it's pretty head about what else I've got hanging off the router. (But does this mean that I've got to keep the G3 for ever and ever? I wonder).

Allen, sinking.

Dark Fiber

22-02-2007, 11:17

We're still not clear- when you attach to the new Mac, can you see the modem web page at 192.168.100.1?
There's a problem with the modem, the Mac or the cable/plugs/sockets. Getting a router will only complicate matters further!

stripes

22-02-2007, 12:00

Hello Dark.

Don't know what a modem web page is. (Just tried that address on this working Mac, the old G3, and got an NTL page with details of the modem, MAC address, etc. I'll do it again (for the nth time) on the new iMac in a minute, but I'll have to shut down to rewire the system. Reporting back later).

Mind you: I've NEVER seen an IP address EXCEPT starting with 169 when connecting to the new iMac.

To repeat, all tests, all different combinations of cable, speeds, etc., ALL come up with 169 IP address.

Allen.

melevittfl

22-02-2007, 12:07

Right, thanks for all those.

I'm connected through the G3 at the moment.

Modem is an 'ntl 250'. Sync and Ready come on. Enet comes on. Disconnecting coaxial changes nothing. IP address under all test conditions comes back as 169...

Just looking at ifconfig. Yes, got to that stage, Mark, but I haven't got any physical connection between the two machines, so can't copy and paste. I know it's very difficult doing this from a distance, but can you tell me what I'm looking for (or rather what YOU'RE looking for)?

Hi, sure no problem.

ifconfig prints out the status of all of the available network interfaces. You're looking for the section that starts with "en0:". That's the ethernet jack.

What I'm interested in is the line that starts with "media:" including the "status:" field.

An example of what is should look like is below:

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 192.168.0.50 netmask 0xffffff00 broadcast 192.168.0.255
ether 00:0d:93:31:08:e8
media: autoselect (1000baseT <full-duplex>) status: active
supported media: none autoselect 10baseT/UTP <half-duplex> 10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback> 100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX <full-duplex,hw-loopback> 1000baseT <full-duplex> 1000baseT <full-duplex,hw-loopback> 1000baseT <full-duplex,flow-control> 1000baseT <full-duplex,flow-control,hw-loopback>

stripes

22-02-2007, 12:37

Right, Dark...

Sorry, thought that was an IP address initially, but now I see what it does.

Okay.

On my original, working machine, the G3, I get:

Cable Modem Information Cable Modem : Euro-DOCSIS 1.0/1.1/2.0 Compliant MAC Address : 00:0e:9b:fd:0d:3e Serial Number : 000E9BFD0D3E Boot Code Version : 2.1.6d Software Version : 2.94.1010 Hardware Version : 1.19

On my new, non-working machine, the iMac, I get PRECISELY the same information, every figure just the same.

I don't know whether this is a good or bad thing! (Don't be fooled - sometimes I might sound as if I know what I'm doing, but I don't.)

Mark:

the line you refer to reads:

media: autoselect (100baseTX <full duplex, flow control> status: active

Does that help at all?

I've copied all the ifconfig data onto a word processing doc on the iMac, so can read it off and retype any other bits you may need.

Thanks again for trying.

Allen.

NTLVictim

22-02-2007, 13:23

If Stripe can see the modem page on both Macs but can only see the Internet on the G3, logically that points at the Imac being refused throughput for some reason...second opinion, please!

melevittfl

22-02-2007, 13:23

media: autoselect (100baseTX <full duplex, flow control> status: active

Does that help at all?

Hi,

OK, well it seems that both the cable modem and the mac are seeing that there is, in fact, a cable plugged in.

That means it's probably not a bad cable.

The fact that you can browse, on the iMac to the 192.168.100.1 address means that the low-level connection is working. I.e., the Mac is able to communicate with the cable modem.

So, we've eliminated a physical connection problem and we know the basic TCP/IP stack is working.

So, it's definitly a problem with the process whereby the mac requests an IP address from NTL and one is assigned.

We don't yet know which end has the problem. I suspect it's a strange iteraction between the two.

One thing, you mentioned you have a new Mac. Can you click on the Apple icon in the top left of the screen and click "About this Mac".

There should be something that should exactly the version of OS X it's running. I.e. 10.4.SomeNumber.

NTLVictim

22-02-2007, 13:40

I said that, but I was more concise.;)

---------- Post added at 13:40 ---------- Previous post was at 13:32 ----------

Is this germane to the problem?

http://macosx.com/tech-support/problem-with-obtaining-ip-address-from-dhcp/12602.html

stripes

22-02-2007, 13:45

Mark: it's10.4.7, so very late.

NTLVictim: I agree, most of the experts round here agree. So who doesn't? That's right, NTL. But WHAT CAN I DO? I'm quite prepared to go Sky or someone else for all services (and thus hopefully get a working broadband).

When questioned on this, the guy on ntl's phone said that they Couldn't do manual resets, they DIDN'T do manual resets, and they didn't NEED to do manual resets, as the SYSTEM (gord help us) was fully automatic, and did its own resets.

So what can I do? I paid eight hundred quid odd so that I could have a nice new machine (after ten years it seemed about time), and I don't want to have to keep two Macs, one for talking to you guys, and one for non-www stuff.

Help......

Allen.

Dark Fiber

22-02-2007, 13:48

If Stripe can see the modem page on both Macs but can only see the Internet on the G3, logically that points at the Imac being refused throughput for some reason...second opinion, please!

I agree that is by far the most likely situation, with the proviso that there could be a hardware/software problem with the iMac.
I know that the cable system is supposed to provide more than one address so that a different MAC can be connected and receive an IP address without a restart, but I would now turn the modem off for an hour and then start up the new computer only after the modem has been powered on with lights stabilized for a few minutes.

stripes

22-02-2007, 13:52

NTLVictim: interesting post on that link, but no lightning strikes round NW9 in the past week! However, I might try taking my set-top box off and see what happens - it's not directly connected. Cable comes in the wall, then a splitter sends one signal to STB and one to cable modem.

Dark: tried full power down for twenty hours the other day (see an early posting) without success. Do you think it's worth doing it again?

Allen.

Dark Fiber

22-02-2007, 13:56

Dark: tried full power down for twenty hours the other day (see an early posting) without success. Do you think it's worth doing it again?

Allen.

Yes, but not for that long :)
If this fails with the iMac, immediately switch the ethernet to the G3 without a modem restart.

melevittfl

22-02-2007, 14:06

I said that, but I was more concise.;)

---------- Post added at 13:40 ---------- Previous post was at 13:32 ----------

Is this germane to the problem?

Yup, bad habbit of mine. ;)

I don't think the issue is the same as he's already gotten a replacement iMac from Apple.

maverick

22-02-2007, 14:06

What I cant understand is that the modem config page can be viewed on the new mac with a 169 ip address,this should not happen.
Any mac bods out there confirm if the mac address of the working mac can be cloned onto the new mac?
If this is possible it would be worth a shot.

NTLVictim

22-02-2007, 14:08

What about the bit that said

"On the iMac open your preferences, select Built-In Ethernet from the list, then click on Configure. Click on the TCP/IP tab and set the Configure drop down menu to DHCP. Click on Apply Now, then quit Network.

Turn off the the ] (http://macosx.com/tech-support/problem-with-obtaining-ip-address-from-dhcp/12602.html#) modem and the computer and wait about five minutes. Then turn on the cable modem and wait until the status indicators show it's communicating with the network. Then power up the (http://macosx.com/tech-support/problem-with-obtaining-ip-address-from-dhcp/12602.html#). See if this gets your connection re-established properly."

I'm guessing, I'm using Xp Pro..:confused:

melevittfl

22-02-2007, 14:11

Stripes,

From the Terminal application again, can you please type the following command:
ipconfig getpacket en0

(notice it's ipconfig with a "p" this time).

I'm interested in the lines that start
op =
yiaddr =

in particular.

NTLVictim

22-02-2007, 14:13

Whoa, hang on..STB?

STB's don't like different mac addresses, is this interfering with the SACM somehow??

Chris W

22-02-2007, 14:14

Try changing the mac address of the ethernet card on the new mac to the same as it was on the old mac by doing the following:

To find the mac address on the old mac, go to apple -> control panel -> tcp/ip -> ethernet. Then go to "get info" from the file menu and write down the mac address.

Then on the new mac check which interface the ethernet card is - it will be en0, en1, en2 etc depending on whether you have an airport card, dial up modem etc. When you have identified this open terminal and type the following:

sudo ifconfig enX lladdr [new mac]

where X corresponds to the ethernet card, and [new mac] is the mac address from the old mac.

Then reboot everything and connect up the cable modem... hopefully this should get you sorted :)

stripes

22-02-2007, 14:39

Sorry, this is going to be a bit slow, as any iMac / internet testing means I have to disconnect this machine.

Anyway...

Dark: I will try the longer powerdown shortly. As it happens, I DID just pull the ethernet from the iMac and stick it back into the G3 WITHOUT rebooting the other day (fed up with waiting) and the internet connection worked fine on the G3. Haven't tried it the other way round, though.

NTL victim: see answer above to Dark. I will do what you suggest, but I have done that dozens (no joke) of times already.

Mark: no go with the ipconfig getpacket en0 prompt:
Just gives me back
localhost:- allen..... etc. no other data.
(Mind, ethernet currently disconnected. I'll run that test again in a min. when I've connected iMac to modem).

NTLVictim. As I stressed, STB isn't directly on the circuit with the modem. NTL cable comes in the wall, to a splitter (ntl fitted all this, of course). From the splitter one cable goes to the STB, one to the modem. I COULD disconnect the STB (i.e. pull out ITS coaxial) if that would help isolate it. Yes/no?

Chris W. I'll have a got at that lot, and report back when I get stuck.

Allen.

NTLVictim

22-02-2007, 14:44

My money is on what Chris said will work.

Can a STB on the same line cause this problem? anyone know?

stripes

22-02-2007, 14:51

Chris: just noticed that you say ''then connect the modem'' etc., so I did that on Terminal while I was still unconnected. Took the string, came back with:
We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things....

blah blah.

then: Password. Tried putting in my iMac password, but wouldn't take any more keyboard input.

Now to switch ethernet and reboot all...

Allen.

melevittfl

22-02-2007, 15:02

We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things....

That's the message that the "sudo" command prints the first time it's run. It shouldn't do that a second time.

It should accept the password, but it won't display anything while you're typing so it may look like it's not working.

NTLVictim

22-02-2007, 15:21

Information on the sudo command Here (http://en.wikipedia.org/wiki/Sudo)

stripes

22-02-2007, 15:57

So, tried that lot.

Tried inputting the sudo command string to no effect. Still says 'not connected to the Internet on launching Safari'; still reverts to a 169 address on Network pane.

Tried just pulling the ethernet out of the modem and reconnecting the G3 ethernet line instead. No go, had to powerdown and reboot etc. (As it happens, got a strange 'Scripting OSAX' message which screwed up Netscape and Outlook Explorer, but which seems to have gone away now, thankfully).

Tried the modem on for five minutes first, before booting Mac. No go.

So, I shall now pull the coaxial from the STB, without much hope of success, and report back again shortly.

Allen.

Chris W

22-02-2007, 16:12

hmm. How very bizarre.

When you do ifconfig is it now showing the same mac address on the new Mac as it is on the old one? (just to confirm that the sudo command has worked).

If the mac addresses are the same, this tends to point to a problem with the Mac (bizarre as it seems) because if the two devices have the same mac address, as far as the cable modem and the network are concerned they are the same device.

I don't suppose on the intel Mac you have bootcamp installed and dual boot with XP or Vista do you?

Dark Fiber

22-02-2007, 16:17

The following is a Q&A in a sample paper for the "Mac OS X Support Essentials v10.4 Exam"

"You are using DHCP to distribute IP addresses on your corporate network. One of
your computers has a self-assigned IP address. How can you force this computer
to attempt to acquire a DHCP address? (Choose TWO.)
A. xxxxxxx
B. Enter a new DHCP Client ID in the Network preferences and click Apply.
C. xxxxxxx
D. Set a manual IP address in the Network preferences and click Apply, then
change to Configure Using DHCP and click Apply"

I suggest trying 'D'

NTLVictim

22-02-2007, 16:17

May I suggest big M for the Macintosh and small m for mac address?

I'm getting dizzy, is all..

Dark Fiber

22-02-2007, 16:25

May I suggest big M for the Macintosh and small m for mac address?

I'm getting dizzy, is all..

Definitely not! Media Access Control = MAC
Macintosh computer (often wrongly referred as a MAC) properly referred to as a Mac

PS And what were the idiots at Ofcom thinking when they coined "Migration Authorization Code" for ADSL transfers? :)

stripes

22-02-2007, 16:36

Chris: not sure what I'm looking for on the ifconfig result data.

one line reads inet 127.0.0.1 netmask etc.

another line reads ether 00:17:f2:d0:f7:bb

and another reads lladdr 00:19:e3:ff:fe:6c:6a:94

None of which bear any resemblance to the 213 etc address of my old G3.

(When we set up the G3 connection 2-3 years back, the ntl man gave me these figures to keep:

00:0e:9b:fd:0d:3e
ntlct8cj486

but I don't know what they mean, needless to say.)

So does the sudo command appear not to have worked? If not, and you think it's worth a retry, could you confirm whether or not the iMac should be connected to the modem at that point?

No, no bootcamp installed.

MAC for MAC addresses, Mac for Apple Macintoshes. Do?

Dark: you write...
set a manual IP address in the Network preferences and click Apply, then
change to Configure Using DHCP and click Apply"

Been there, etc., but I'll do it again if you want. What figures should I put in, and where?

Allen.

NTLVictim

22-02-2007, 16:39

Stripe, massive respek to Dark, but try Chris's first..looks like the MAC didn't take.

Dark Fiber

22-02-2007, 16:44

(When we set up the G3 connection 2-3 years back, the ntl man gave me these figures to keep:

00:0e:9b:fd:0d:3e
ntlct8cj486

MAC for MAC addresses, Mac for Apple Macintoshes. Do?

Dark: you write...
set a manual IP address in the Network preferences and click Apply, then
change to Configure Using DHCP and click Apply"

Been there, etc., but I'll do it again if you want. What figures should I put in, and where?

Allen.

That's the (WAN facing) MAC address of the modem, and a code used for initial registration of an NTL account.

Shouldn't matter as you're just prodding the OS, I would enter 192.168.0.1
In the IP address box that appears when you set the Configure IPv4 pulldown to Manually

Chris W

22-02-2007, 16:47

That MAC address is wrong- it should be 12 hex characters.

Try using

sudo ifconfig enX ether [new Mac]

instead. Might get the address changed properly.

stripes

22-02-2007, 16:50

Fellows (sorry if any non-fellows replying).

You're starting to treat me as if was an engineer who knew about things. I am not an engineer. I do NOT know about things. I am just doing, robot-like, each thing you tell me.

Also, assuming on the gloomy side that none of this cures the problem, will any of the 'tampering', i.e. with the Terminal string inputs, cause any collateral damage down the line?

Anyway, I've got to switch off now, as I've been on the darned thing most of the day and have got a blinding headache!

I shall come back to it, fresh (?), in the morning, and do what I can.

Thanks for your time. (And is it just me, or are there loads more 'ntl broadband modem problem' messages lately?)

Allen.

Dark Fiber

22-02-2007, 16:52

try Chris's first..looks like the MAC didn't take.

I don't think you can modify/"clone" a computer's MAC in OS X and very much doubt it would survive a restart even if you could.

Chris W

22-02-2007, 16:56

I don't think you can modify/"clone" a computer's MAC in OS X and very much doubt it would survive a restart even if you could.

yes you can... i think i gave the wrong command the first time though, and it should be the second one that i posted that does the job

NTLVictim

22-02-2007, 17:38

Bleedin' ntl..

Stripes, when you come back in the morning, I found this;

" % sudo ifconfig en0 ether aa:bb:cc:dd:ee:ff

where en0 is the network interface (numbered from en0, en1, en2 ...) and aa:bb:cc:dd:ee:ff is the desired MAC address in hex notation."

Which is what Chris said only in a different way, if that helps.
Chris, can you verify that syntax above, I'm no expert!

Another thing is Stripes' Belkin router may turn up tomorrow, and they have a very handy cloning button in their routers webpage interface, which may be a better way to go?

Dark Fiber

22-02-2007, 17:52

yes you can... i think i gave the wrong command the first time though, and it should be the second one that i posted that does the job

After much Googling, I see you are correct for OS X 10.4 [ Earlier versions of OS X required kernel patching :Yikes: ]
While this tactic may be useful here as a diagnostic, I can't help feeling that the problem should be able to be solved more simply.

The WWW is full of problems where IPs are self-assigned because DHCP servers don't respond quickly enough or clients time-out too quickly. There seems to me to be a hint that Intel-chipset based Macs may suffer from the latter.

---------- Post added at 17:52 ---------- Previous post was at 17:43 ----------

Bleedin' ntl..

Another thing is Stripes' Belkin router may turn up tomorrow, and they have a very handy cloning button in their routers webpage interface, which may be a better way to go?

What will be interesting is whether the router's "native" MAC works out-of-the-box. There should be no need to clone anything :) unless the problem actually lies with his cable connection ;)

parky

22-02-2007, 18:19

Is this not a 'Provisioning' problem?

Chris W

22-02-2007, 18:22

Nope- provisioning a new device only applies when using a set top box connection, stripes is connecting through a cable modem.

NTLVictim

22-02-2007, 18:26

Yes, but if there was no need to clone anything, this thread would not exist...:)

I still think the STB may be involved in getting snotty with different IP addresses because we have heard nothing to the contrary, no February-joining VM acolytes have raised their heads above the parapet on this thread...:scratch:

Any VM techies out there? echo, echo, echo...:D

Dark Fiber

22-02-2007, 18:33

Yes, but if there was no need to clone anything, this thread would not exist...:)

If people didn't think there was a _need_ to clone something, this thread would not be as long ... :)

NTLVictim

22-02-2007, 18:37

Dark, this about ntl..we ain't talking about human beings here!:D

monkey2468

22-02-2007, 18:44

Stripes, not sure if this has already been asked, but do you have a firewall installed? If so try uninstalling it.

Dark Fiber

22-02-2007, 18:47

Dark, this about ntl..we ain't talking about human beings here!:D
Human cloning - you are cynical ;)

I'm inclined to blame the VM/ntl connection but that's because I'm loath to admit that sometimes nowadays Macs don't "just work" :(

I hope prodding the OS in the way that Apple themselves suggest will do the trick. We Mac enthusiasts want to be shielded from the awesome power of Unix by the Mac GUI. If we can't solve this without "sudo" then we're in deep trouble!

PS His OS X firewall shouldn't be on by default

werdna12

22-02-2007, 19:25

I don't know if this has been mentioned already in this thread, but I would invest in a wireless router.

Late last year I purchased my first ever mac. The Mac Airport inside my Imac Pro detected the wireless router straight away and without any setting up I was up and running on the world wide web.

It was very simple all I had to do is make sure that airport was running in preferences and then click on the wireless icon near the clock & select my wireless network from the list.

Also allows you to use your mac anywhere in the house.

NTLVictim

23-02-2007, 08:56

Stripes has a Belkin router on it's way, dunno if it's wireless or not..still, running a few cables in the meantime is no big deal.

I've just realised why Belkin is Mac approved..it's running the airport chipset, right? :)

stripes

23-02-2007, 08:59

Right. Good morning, all. Here are my overnight thoughts and responses to your posts last evening.

TECHNICAL.

ChrisW. Tried sudo if config en0 ether 213.xxx.xxx.173 [enter] (xxx for security reasons)
password: (typed the only one I know, i.e. mine) [enter]
ifconfig: malformed ether address
(then retried using what ntlvictim recommended, i.e.....
% sudo if config en0 ether (then what I think is a hex address from same Get Info panel on G3 - ) 00.05.02.xe.xx.xx (x security reasons)
[enter] (came back)
-bash: fg: %: no such job

So no great joy with that. Probably me.

And yes, I am expecting that belkin router this morning, so will read all the blurb v.carefully before doing anything with it. (Interested to see that you haven't ruled it out, though).

Don't understand your internal discussion re cloning etc., so ignoring it.

Monkey, no firewall, unless the Mac has something built-in, and I don't think it has.

Werdna, getting a non-wireless router this morning, but I fear a wireless one would really add to the potential problems!

BIZARRE ALTERNATIVES

If we can't solve this between us, with some of the best brains in cable/modem etc. technology (on your side of the fence, that is), then what do I do?

a) does anyone know the name of the Mr Big at ntl, and address? I will write to him direct (old-fashioned ink and paper) throwing myself on his mercy and begging for help.

b) does anyone (and I know this is probably against some rule or other) live within driving distance of NW9, and is willing to come round for a few hours on a payment-by-result basis for, say, Ãƒâ€šÃ‚Â£100 in crisp notes, to get this lot fixed? If so, Private Message me, and if the sum ain't enough, tell me what would be.

Responses on the Technical side: please remember that I am a VERY ordinary Joe. I might be able to type, and be reasonably articulate, but, like Manuel, I KNOW NOTHING. So please keep it simple!

Look forward to hearing from you.

Allen.

NTLVictim

23-02-2007, 09:03

We are with you.:)

Graham M

23-02-2007, 09:11

its

ifconfig

not

if config

Dark Fiber

23-02-2007, 09:25

I know this is very upsetting for you, and so many sources of advice must be a trial. We all want to help.

Have you tried the Apple way to force a DHCP lookup that I put forward?

If the router turns up, try using it out-of-the-box with no cloning. It's really just trying a third computer that hopefully may pick up the IP address without problems. (I have to say that if you already had a router, our advice would have been to remove it and connect the iMac directly to the modem!)

I'm going to shut up now- you want a resolution of your problem (while I'm actually trying to find out if there is a global problem with VM/ntl and Intel Macs)

NTLVictim

23-02-2007, 09:41

I'll shut it as well, get back to us..for the record, I think cloning the MAC address of the G5 onto the belkin router will work.

Alright, I'm going...:D

stripes

23-02-2007, 10:06

Thanks, as usual.

ntlvictim: it really is a source of comfort that interested and intelligent people are with me, and no, I am not being ironic. It helps.

zeph: yes, sorry, ifconfig. I was typing on 2 keyboards at the time.

dark: I'm pretty sure I've tried the DHCP lookup, but not in the sequence you defined, so I will shut this one down shortly and try it.

And yes, when the Belkin turns up I will first of all just plug it in without doing anything fancy to it.

Talk to you all later.

Allen.

melevittfl

23-02-2007, 10:37

ChrisW. Tried sudo if config en0 ether 213.xxx.xxx.173 [enter] (xxx for security reasons)
password: (typed the only one I know, i.e. mine) [enter]
ifconfig: malformed ether address
(then retried using what ntlvictim recommended, i.e.....
% sudo if config en0 ether (then what I think is a hex address from same Get Info panel on G3 - ) 00.05.02.xe.xx.xx (x security reasons)
[enter] (came back)
-bash: fg: %: no such job

Hi,

In that first command that Chris gave you, you'll want to type the hex addresses, rather than the numeric IP address. That is, it should look like:
"sudo if config en0 ether 00:05:02:XE:XX:XX" (substitute the real values for the Xs as you did before and don't include the quotes).

The second time you ran the command, it looks like you included the "%" character. I think NTLVictim included that to show you what the command prompt looked like, but it wasn't meant to be part of the command itself.

NTLVictim

23-02-2007, 10:39

Stripes, while you're waiting for the router to turn up, have a read of this Belkin Manual (http://web.belkin.com/support/download/files/F5D5231-4_manual.pdf) particularly page 30..your manual maybe slightly different, but it'll give you an idea.

stripes

23-02-2007, 12:06

So...

ntlvictim. Thanks for that reference, I'll have a look in a minute.

Mark. Now, maybe progress.
On the iMac, with the ethernet disconnected from the modem, I have just entered the modified sudo string, and, BEARING IN MIND THAT I DON'T KNOW WHAT I'M LOOKING AT OR FOR!, in the data that's come back, under en0:, the 'ether' line does now read just the same as the hex string I just put in.

So, if that means that the iMac now has the same address as the G3, will this fool the modem?

Only way to find out is to replug and try it, so I'll be back in a few minutes.

Allen.

melevittfl

23-02-2007, 12:10

Only way to find out is to replug and try it, so I'll be back in a few minutes.

The suspense is killing me. :):)

The cable system uses that identifier to uniquely identify the devices on the network. There is a limit to the number of devices that the cable system will allow to connect. When a machine starts up, it asks the cable system for an IP address to use and, the cable system uses the ethernet id to track which machine has which IP address.

It's supposed to allow two devices without having to wait for one to timeout, and even so, leaving the cable modem off for 20 hours (as you mentioned you tried) should have cleared any pre-existing entries.

The theory we're working on is that somehow that's not happening and the cable modem only wants to assign an IP address to the ID used by the G3. By telling the iMac to pretend it's got the same ID as the G3, we're testing out theory.

Cheers,
Mark

stripes

23-02-2007, 12:49

Mark: sorry for the time it takes - apart from pulling cables in and out, the G3 takes ages to boot up, and if I have been a bit too speedy, has to be rebooted etc.

So, no go again, I'm afraid.

Having got that hopeful ether set of figures the first time, once I connected the iMac to the modem and rebooted everything, still 169.

I tried ifconfig at that point, and sure enough, the ether figures are no longer the ones I put in 45 mins ago for the G3, they are a different set entirely, which I don't recognise.

I then tried the sequence that Dark had recommended, i.e. manual dhcp, apply, dhcp, apply, but still no go. I test the machine at that point in 2 ways - one, seeing what address is returned on Apply Now or Renew DHCP lease, and noting it (although it always starts with 169), two, launching Safari (browser) just to make sure I'm really not connected to Internet.

And the sodding router hasn't turned up. Which probably means tomorrow morning, as we tend only to get van deliveries in mornings. Ah well.

I also pulled the coaxial out of the STB, just in case, but no difference, except I couldn't watch Judge Judy.

I still the like the idea of making my iMac have the same name as the G3, but that route doesn't seem to have done it.

More later, hopefully...

Allen.

---------- Post added at 12:49 ---------- Previous post was at 12:42 ----------

ntl victim: just had a v.quick glance at the Belkin link, and yes, that's why I'm thinking on these lines.

You set up the router with the G3 details, and it's happy. You then stick in the iMac ethernet line, and the modem/router combination doesn't care about another machine's address, only that precious first G3 address.

That's what I'm hoping for! (With my luck, I shouldn't still be an optimist).

I'll report back when something happens.

Allen.

melevittfl

23-02-2007, 12:51

Having got that hopeful ether set of figures the first time, once I connected the iMac to the modem and rebooted everything, still 169.

I tried ifconfig at that point, and sure enough, the ether figures are no longer the ones I put in 45 mins ago for the G3, they are a different set entirely, which I don't recognise.

OK, it might reset them when it reboots.

So, give it one more try (if you're not sick of it. )

This time, plug the ethernet cable into the iMac and power on the cable modem and then the iMac, let it boot. THEN, try the ifconfig command to change the id to the one on the G3.

Cheers,
Mark

Dark Fiber

23-02-2007, 12:55

I then tried the sequence that Dark had recommended, i.e. manual dhcp, apply, dhcp, apply, but still no go.

Allen.

Sorry to be pedantic- you do mean manual ip, apply etc. ?

There is a (rather dated) procedure from Apple <http://docs.info.apple.com/article.html?artnum=106879>
that involves resetting the interface. Again a typical change-it then change-it-back tactic that goes back at least to when I started using Macs in 1987 ;)

I've nailed my colours to the mast:
"Mac enthusiasts want to be shielded from the awesome power of Unix by the Mac GUI. If we can't solve this without "sudo" then we're in deep trouble!"

The tactics I advocate talk directly to the Unix layer but do so via the Mac OS X GUI, leaving less room for error.

BTW why are you still on 10.4.7?
NB It would be v.informative if the router worked _without_ being cloned with a machine MAC

NTLVictim

23-02-2007, 12:59

Just found this; "Some say it doesn't work because it doesn't change the MAC in the GUI, and because it reverts after a restart..."

Is this true?

parky

23-02-2007, 13:04

BTW why are you still on 10.4.7?

Because he can't connect to the internet to get the 10.4.8 update!

---------- Post added at 13:04 ---------- Previous post was at 12:59 ----------

Monkey, no firewall, unless the Mac has something built-in, and I don't think it has.

Mac OS X does have a built in Firewall.
Go into system preferences, and then Sharing, then click on the 'Firewall' tab.
It will either say 'Firewall On' or 'Firewall Off'.
If it is on, turn it off, just click the 'Stop' button.

Ian

Dark Fiber

23-02-2007, 13:11

Because he can't connect to the internet to get the 10.4.8 update!

---------- Post added at 13:04 ---------- Previous post was at 12:59 ----------

Mac OS X does have a built in Firewall.
Go into system preferences, and then Sharing, then click on the 'Firewall' tab.
It will either say 'Firewall On' or 'Firewall Off'.
If it is on, turn it off, just click the 'Stop' button.

Ian

:dozey: Let me rephrase that. Did you get the machine through normal retail channels?

As I pointed out earlier:
1) the OS X firewall is off by default (and I haven't heard of it interfering with DHCP requests which of course it shouldn't :) )

2) I am worried about this workaround not surviving a restart.

stripes

23-02-2007, 13:44

So, in order.

Mark: tried that, precisely as instructed. Data on final ifconfig comes back as before, i.e. reading the G3 address in the 'ether' line. But how do we hold it there? Just doing another restart as I type, so.... no again, on restart, ifconfig, data changes so that the ether line reads a different set of figs.

Dark: bought it from Apple themselves, two weeks back. Well, that was the first iMac. After a week I convinced them it was faulty and I am now on my SECOND brand new iMac, still from Apple. Couldn't be MORE legal than that.
10.4.7 cos it came with the machine. As Parky points out, if I was connected to the internet on the OSX iMac I might download the upgrade!

Dark again: PEDANTIC I like, in these situations. It's necessary.
I went to Network Pane, Configure ipv4, chose Using DHCP with manual address, put in the address, Apply Now; went back to Configure ipv4, chose Using DHCP instead, hit Apply Now. No go.

Firewall is OFF.

When/if the Router turns up, I will try it first with no cloning, just whatever basic set-up procedure it says. If no go, then I'll try the clone option (if I understood it properly it would help, but I'm beginning to grasp the concept).

Guys, I've got to disappear for an hour or two (went blind in one eye the other week, so a tedious hospital visit today [that's what I meant by my luck]) so will have to go quiet for a bit.

There's someone here in case the router turns up!

(What I really, really want is a Father or maybe a Son, who would come round here, sit me in the corner to play, while he pressed a few buttons and fixed the problem, then take me by the hand and sat me down at my computer. Still, you lot couldn't be trying harder, and I do appreciate it).

Allen.

NTLVictim

23-02-2007, 13:53

Stripes, just found this VIDEO (http://homeoffice.consumerelectronicsnet.com/articles/viewarticle.jsp?id=91867-0)..

scroll down the page to the video window and click play..the resolution is rough, but the narrator explains it well. He's using a lynksys in the demo, but the principle is the same.

Sam

Dark Fiber

23-02-2007, 13:53

Dark: bought it from Apple themselves, two weeks back. Well, that was the first iMac. After a week I convinced them it was faulty and I am now on my SECOND brand new iMac, still from Apple. Couldn't be MORE legal than that.
10.4.7 cos it came with the machine. As Parky points out, if I was connected to the internet on the OSX iMac I might download the upgrade!

Wasn't suggesting illegality, just PC World which is worse :)
It's just that Apple's supply chain is now very short ("just in time") and I thought 10.4.8 had been going out with new machines from Nov 2006.

melevittfl

23-02-2007, 14:40

Mark: tried that, precisely as instructed. Data on final ifconfig comes back as before, i.e. reading the G3 address in the 'ether' line. But how do we hold it there? Just doing another restart as I type, so.... no again, on restart, ifconfig, data changes so that the ether line reads a different set of figs.

Dark again: PEDANTIC I like, in these situations. It's necessary.
I went to Network Pane, Configure ipv4, chose Using DHCP with manual address, put in the address, Apply Now; went back to Configure ipv4, chose Using DHCP instead, hit Apply Now. No go.

Stripes,

OK, almost there I think. Can you try doing what I've suggested above again and then, without restarting, do what Dark suggested.

As NTLVictim says, the solution won't stick when you restart, but if cloning the ethernet ID works, then you can go back to NTL as it would indicate a definite problem on their end.

Hope everything goes OK at the hospital.

freakfunk

23-02-2007, 21:43

Do What I Dont - Probaly Been Said Before But I Aint Reading All The Posts- Buy A Router! The Best Way!

Dark Fiber

24-02-2007, 04:09

Can I put my head above the parapet to put forward some insomniac speculations and a prediction to explain why I keep on about using the long-awaited router without cloning and why I have such reservations about using "sudo ifconfig" in the way suggested?

BTW Stripes, did you originally connect the G3 through the set-top box (STB) and later get given a stand-alone cable modem (SACM)?

All the original problems, with not one but two iMacs failing to pick up an IP address and reverting to the self-assigned 169. address and, more significantly, not being able to be jolted out of that state, would be consistent with the cable system treating your SACM as though it was (the modem part of) your STB. STBs are "provisioned" to work only with a single client MAC while the system allows SACMs to work with a change of client machines. The prediction is that the Belkin router will not connect with its "native" out-of-the-box MAC setting but will connect when you "clone" the G3's MAC number into it.

Now some thoughts about why MAC "spoofing" with a directly-connected machine might not be exactly equivalent to MAC "cloning" with a gateway router: bear in mind that I am not an IT professional and what little I knew about networking has already been increased by learning that OS X now allows spoofing!

The MAC number is intended to be unique to each Media Access Controller and unalterable as it is "burnt in silicon". "Spoofing" is, after all, usually done for nefarious purposes. The cable system interrogates the Media Access Controller of whatever equipment is directly connected to the SACM and gets back "packets" that contain, among other things, the MAC number of the Media Access Controller. Now, although a connected computer's operating system can be "hacked" to cause IP packets originated by the machine to contain a "soft" MAC number instead of the Media Access Controller's "hard" MAC number, it doesn't necessarily follow that its Media Access Controller will respond to incoming interrogations with packets containing the "soft" MAC number (because Media Access Controllers are designed to be largely autonomous so as to "take the load off the CPU". This is why ethernet connections are vastly superior to USB connections in the context of networking.)
A home gateway router is, however, rather different. Its Media Access Controller is specifically designed to be "programmable" to take account of those ISPs who try to restrict access to a single computer by reference to its MAC number. If cloned with a client machine MAC number, a home gateway router _must_ respond to interrogation with packets containing the new MAC number and indeed use that MAC number under all circumstances.

To sum up- on Stripes behalf, I was reading Ted Landau's monumental tome "Mac OS X Helpdesk" yesterday (!) and he goes so far as to state that "99% of problems when connecting Macs to broadband are the fault of the ISP" and I'm sure that is the case here. However, I don't see how to get VM/ntl to acknowledge that it is their problem and so the use of a router, although regrettable, will have to be the "fall back" solution to the problem. Stripes may find it useful to be able to connect more than one machine from time to time and some people are happier leaving a router on 24/7 and being able to turn off their computer. Personally, I just let my Macs go to sleep- and I will now try to do the same :(

NTLVictim

24-02-2007, 08:55

Regarding Mr Fibre (English spelling ;)):

What he said.:D

Interesting question about the SACM being added after the STB, Id like to hear the answer to that one, it could explain a lot!:)

melevittfl

24-02-2007, 09:26

Now, although a connected computer's operating system can be "hacked" to cause IP packets originated by the machine to contain a "soft" MAC number instead of the Media Access Controller's "hard" MAC number, it doesn't necessarily follow that its Media Access Controller will respond to incoming interrogations with packets containing the "soft" MAC number

Yes, it does. The MAC Id is an address, just like an IP address. The ifconfig command simply tells the hardware to use one address vs. another. It doesn't get confused over which one its supposed to use.

(because Media Access Controllers are designed to be largely autonomous so as to "take the load off the CPU". This is why ethernet connections are vastly superior to USB connections in the context of networking.)

You're mixing up Media Access Controller with Media Access Control Addresses. What you're describing are special ethernet chips that do some of the calculations required for TCP/IP networking that would normally have to be done by the CPU. The MAC address is simply an address, just like an IP address.

A home gateway router is, however, rather different. Its Media Access Controller is specifically designed to be "programmable" to take account of those ISPs who try to restrict access to a single computer by reference to its MAC number. If cloned with a client machine MAC number, a home gateway router _must_ respond to interrogation with packets containing the new MAC number and indeed use that MAC number under all circumstances.

Not really. A home router is pretty much the same as a computer except it uses flash ram instead of a hard-disk. Most of them run Linux (a Unix variant just like Mac OS X). Setting a router to use a cloned MAC address is exactly the same as the ifconfig command. Its software would write a configuration file to the flash ram to make sure that the setting stayed when the router was reset, but you could do that on the iMac as well. It's just software.

Now, that being said, I think having Striper change the MAC address is not a permanent solution either, but it would let him go back to NTL and know it's a problem with their end.

And you're also right that if the router turns up and it works when cloned to the old G3's Mac address, than he may be best off simply accepting that and use the router.

NTLVictim

24-02-2007, 09:42

Routers are also handy for moving stuff and doing backups when you have more than one PC.

stripes

24-02-2007, 09:49

Hallo gang.

It's the router wot won it.

Router set up, after a bit of fiddling (and Dark, wouldn't go unless I hit the CLONE MAC button on the Belkin set-up page), et voila, www access on G3 and iMac.

Now, apart from INCREDIBLE relief (I gave up drinking 5 years ago, but have been sorely tempted in the past weeks), some points.

1. CAN I TURN THE G3 OFF or I am stuck with the machine forever? I shall try disconnecting it a bit later, but I am suspicious.

2. WHAT DOES THIS ALL PROVE (except that you are a great bunch of people, and I am glad you are there)? What does it prove in terms of me having a pop at NTL - if nothing else, to enable me to get my G3 off my desk and down to Oxfam.

3. WWW. It's not about downloading pretty piccies or tunes, it's about this, the exchange of knowledge and information, and as such, utterly invaluable.

4. Didn't try the new form of the sudo string, Mark, as the Router arrived first. And hospital says my blind eye will 'probably' get better. (Probably?)

5. STB has been there for years, and G3 working on ntl broadband alongside the tele, no previous problems.

6. Dark. Thanks a million for your input, particularly getting up in the middle of the night, to boot. No, my choice of words over the 'legal' business was wrong. I meant 'legitimate' in the broader sense, i.e. I would never buy something as complicated as a Mac from the likes of PC World. Ink cartridges, maybe.

So, I sit here smugly, two computer screens on and glowing, waiting for your comments (as usual!)

A happier Allen.

NTLVictim

24-02-2007, 10:37

Yeeeeeeeeeeeeessssssssssssssssssssssss............ .

---------- Post added at 10:06 ---------- Previous post was at 09:57 ----------

May I just take this moment to point out our "add to reputation" buttons on the bottom left of our name boxes? It's next to the little triangle..... :D

Cough...

---------- Post added at 10:37 ---------- Previous post was at 10:06 ----------

Now I've finished jumping about, the router thinks its the G3, so yes, you can do with it what you will, although I'd keep it for data backup etc...

Please make a note of the MAC address if you dispose of it, just in case you need to put the details back into the router, if you upgrade or whatever.

stripes

24-02-2007, 10:49

Hello NTLVictim.

Replying on the iMac. Ain't half quieter.

Well, so far I've turned the G3 off, just (taking screen shots of TCP IP panels etc first for printing out and keeping so I've got the data). Later I'll try pulling the plugs...

I know it's Saturday, but could you have a look at my no.2 question above, i.e. what does it prove? I am not really bothered about having a pop at ntl, it will only arise if I can't disconnect my G3 from the now growing circuitry.

Cheers.

Allen.

NTLVictim

24-02-2007, 11:52

Number 2 is what VM customer services are for fobbing you off...

Oh, question number 2..

It means that NTL/VM ARE blocking access to everything except the G3 via the MAC address, despite their claims that they ain't.

Dark Fiber

24-02-2007, 12:07

I know it's Saturday, but could you have a look at my no.2 question above, i.e. what does it prove? I am not really bothered about having a pop at ntl, it will only arise if I can't disconnect my G3 from the now growing circuitry.

Cheers.

Allen.

In my opinion, the fact that the router didn't work until you cloned the G3 address into it strongly implies (but doesn't prove) that all the problems have been down to VM/ntl because now you've been unable to connect three computers (2 iMacs and the router) when it should have been straightforward.

melevittfl - I don't accept any of your points and my post was as long as it was because I was continually pasteing "Media Access Controller" when I meant hardware and "MAC address" when I meant data :).
In short, even if a machine is set up for "spoofing", I don't see how you can rule out responses (that wouldn't involve the OS software) to ISP interrogation with the "hard" MAC address unless the computer's MAC hardware has some writable registers which for normal use it wouldn't need. Conversely, a gateway router has a Media Access Controller where those registers are able, by design, to be written to. Before cloning, my Belkin router had the same MAC address facing the WAN as facing the LAN- and that's against the rules :)
BTW I'm not claiming to be right, just logical! I would like to hear from any networking guru and any Mac hardware guru about my points.

NTLVictim

24-02-2007, 12:24

Dark, I reckon it proves it..I used to do this stuff for a living, God help me.

Anyway, we won!

melevittfl

24-02-2007, 20:14

I know it's Saturday, but could you have a look at my no.2 question above, i.e. what does it prove? I am not really bothered about having a pop at ntl, it will only arise if I can't disconnect my G3 from the now growing circuitry.

It means that there system, for some reason, is only willing to give an IP address to a device that matches the MAC address of the original machine (the G3).

Make sure that you write down that MAC address in case you ever need to enter it into the router again.

Other than that, you won't need the G3 anymore. The NTL system things your router is the G3 and will assign an address to it. The iMac gets its IP address from the router and the router, as you might guess, routes the data between the iMac and the NTL network.

Glad you've got it working. And, let me say it was a pleasure helping you out. You had an interesting problem and you were very clear about what you'd tried and what the results were.

Good luck,
Mark

---------- Post added at 20:14 ---------- Previous post was at 19:50 ----------

melevittfl - I don't accept any of your points...

OK. Don't know what I can say if this is your stance, but I'll try... :)

In short, even if a machine is set up for "spoofing", I don't see how you can rule out responses (that wouldn't involve the OS software) to ISP interrogation with the "hard" MAC address unless the computer's MAC hardware has some writable registers which for normal use it wouldn't need.

Well, the computer's hardware does have "writable registers." The physical hardware has a bit of programmable data storage that holds configuration data.

The OS is capable of changing the configuration of the ethernet controller by changing the configuration data. The ability to change the MAC address uses exactly the same mechanism as setting the ethernet controller to full or half duplex and telling it to auto-negotiate the link speed or setting a specific one. It's stored in a re-writable EEPROM that's part of the ethernet controller.

If you don't believe me, there's Wikipedia:

From http://en.wikipedia.org/wiki/MAC_address
"A locally administered address is assigned to a device by a network administrator, overriding the burned-in address."

I would like to hear from any networking guru and any Mac hardware guru about my points.

You mean, other than me?

:)

Cheers,
Mark

Dark Fiber

24-02-2007, 20:45

NTLVictim

24-02-2007, 20:59

stripes

25-02-2007, 09:50

Just an afterthought, gang.

I shall be contacting Apple to do my own grovelling, (after all, thanks to me/ntl they took back a perfectly good brand new iMac!) but also to suggest that they set up some communication with the broadband cable suppliers, so that in future situations like this, they can phone direct and try and sort out the problems, rather than doing the conventional thing (very un-Apple) and relying on their customers to become piggy in the middle.

After all, although I'm certainly up and running and all the help you've given has preserved my sanity through this lot, we didn't actually FIX the problem, did we? (Viz: this morning I plugged my iMac into the modem, bypassing the router, and, of course, I wasn't connected to the internet. So, if my router blows up next month, I'll be almost back to square one (at least till I can buy a new router!)).

Allen.

melevittfl

25-02-2007, 10:09

Mark,
<Grovel Mode ON/ It may amuse you to know (or it may annoy you intensely!) that my speculations were based on a mistake. I wrongly thought that Stripes had _successfully_ spoofed the G3 MAC address into his iMac and that this had _not_ permitted connection to the cable network.

Ahh. Yes, I can see how that would lead you down that line of thinking. No worries. I hope I didn't come across badly in my reply.

Thank you for the Wiki info, it will take some time to assimilate. I note that the Wiki includes the phrase "if the service provider is able to detect that a MAC address is spoofed". How would this be achieved if the spoofed hardware is truly _identical_ in its responses to unaltered hardware? Do you, in fact, believe that the MACs in home gateway routers are identical with those installed in computers?

Yes, the ISP could detect a cloned address, but it's nothing to do with the hardware. One possible way is simply by seeing if the data "makes sense". If you notice, the default, or "burned in" address starts with a sequence that is unique to a particular manufacturer. So, Belkin routers will have a MAC address that starts with XX:XX:XX (for example), and Apple computers will have a MAC address that starts with YY:YY:YY.

Now, the TCP/IP stack (the bit of code that implements the TCP/IP protocol) of an operating system has characteristics that usually allow it to be identified. That is, by simply connecting to a networked device, it is often possible to determine which operating system it is running. If you search for a program called NMAP, you'll find an example of a program that does just that.

So, lets take Stripes' situation. NTL can look at the (now cloned) MAC address and determine that it was assigned to Apple. However, if they scan the machine, they will see that it's not running Apple's OS X, but rather an embedded OS (Linux perhaps). This gives them a clue that the MAC address has been cloned.

There are other ways, but they generally rely on the same kinds of things, rather than on any difference in the address itself.

As you can see, it's not a foolproof process and it takes a bit of detective work, so I doubt most ISPs bother.

Dark Fiber

25-02-2007, 10:39

Just an afterthought, gang.

I shall be contacting Apple ... to suggest that they set up some communication with the broadband cable suppliers, so that in future situations like this, they can phone direct and try and sort out the problems, rather than doing the conventional thing (very un-Apple) and relying on their customers to become piggy in the middle.

After all, ..., we didn't actually FIX the problem, did we? ... So, if my router blows up next month, I'll be almost back to square one (at least till I can buy a new router!)).

Allen.

1) Good luck with Apple UK, I'm afraid that they would take the view that this was such an oddity that an Apple/VirginMedia hotline would not be cost effective.

2) No, it's up to VM/ntl to put this right for your connection. Again, I doubt that a frontal attack would be any use. However, there are lurkers here at CF with hotlines to VM/ntl and it would be interesting to see if they could achieve anything or if it's just a coat of red paint ;)

Mark, your unworthy student bears the marks of his guru's whip upon his back with pride :D