[malvarru]

I have cable internet through comcast (the only choice where I live, NJ). Actually, I should say I had cable internet. About two weeks ago the service was down. My computer (g4) stopped getting ip addresses from the server, and was assigning its own (by default: 169.xxx.xxx.xx). Several calls to customer service confirmed that the modem was working fine. I called a Mac service repair technician to come and take a look at my machine. 269 dollars and an upgrade to Os X.2 later, I still had the same problem. I took the computer to the nearest mac store and it was working fine there (getting the right ip, etc). Finally the cable company sends a technician of their own. The man, upon seing that I had a mac said: "I can not do anything. This has been a common problem with macs in the last two weeks. They suddenly become unable to get ip addresses from the server".

Is anybody else out there with the same problem? Does anyone know what is the problem and, perhaps, how could I fix it (since the comcast people can't?)

Thanks. At this point any help would be greatly appreciated.

[aaanorton]

How do you have your Network Pref pane>Ethernet prefs set?
Try changing the order of the DNS servers.
If all else fails, try a cable/DSL router, but I don't think a Mac should make a difference. How did they confirm the modem was working? Did the Comcast guy test this?

Oh, and you might want to post this to the networking forum as well.

[fulmer]

a router won't do much--you still need that modem.

here's what I recommend:
power off your ethernet cable modem. shut down your mac. power on the cable modem, power on your mac.

do you have another computer to test with?

since it worked at the apple repair place, you know it's not your ethernet port on the mac.

tech support people don't know much.

[malvarru]

Thank you, I realized I posted the message in the wrong forum. I moved the topic to the networking one.

[aaanorton]

Originally posted by fulmer:
a router won't do much--you still need that modem.

A router would put an (non-Macintosh) interface between the Mac and the cable modem. This could solve the problem, as many (shite-faced) ISPs block certain MAC addresses, like those on a Mac, to prevent IP sharing over Airport.
I'd say that IF you had it working, it now isn't AND you've trouble-shooted (shot?) it, then Comcast has filtered you out. In this case, get a router (make sure it bridges AppleTalk) and use it's MAC address. If that address doesn't work, clone one from a PC.
And don't forget to call and pleasantly thank Comcast for their service! Stupid, greedy, incompetent, petty crooks such as they are. Oughta' be a law. Also, make sure you're not being charged for this down-time.

[Avon]

Originally posted by malvarru:
My computer (g4) stopped getting ip addresses from the server, and was assigning its own (by default: 169.xxx.xxx.xx).

It's not a mac issue. They are all quick to blame the loss of connection on a mac.

I have had Comcast@home, now comcast since 1999.

Im willing to bet

Assuming your prefs are right, (just set to DHCP) I am willing to bet its the following...

1 - bad cable.
2 - cable hooked up to a dead port on a hub.
3 - hub not hooked up right if you have one, check uplink...

I have had the exact same problem manyatimes.

Also, if you pluged the modem into another computer, reset it, it remembers the MAC adress of the ethernet card.

It has to work, wether mac, pc or unix machine, there is no diffrence.

[aaanorton]

Originally posted by Avon:

It has to work, wether mac, pc or unix machine, there is no diffrence.

Agreed. Unless, of course, Comcast has crippled it's system. It's my understanding (Can anyone verify this?) that a manufacturer, say Apple Computer, is assigned a range of MAC addresses to pool from. Now, if an ISP wants to disallow any Airport base station from connecting to the network, it would only need to figure out which of the assigned MAC addresses refer to the base stations and block them. Even simpler, however, would be to just block every MAC address assigned to Apple.
So while it shouldn't make a difference, it can make a difference.

[Avon]

Originally posted by aaanorton:


Agreed. Unless, of course, Comcast has crippled it's system. It's my unders however, would be to just block every MAC address assigned to Apple.
So while it shouldn't make a difference, it can make a difference.

I don't think thats possible or even legal. If they did all you would have to do is buy an ethernet card. The only way you cant access certain high speed internet connections is with companies that use propritary software for the PC that verify who you are before you sign on. I dont thin there are many ISPs that do this anymore, its bad for business, not everyone owns a PC.

Once again, I have had Comcast for 3.5 years. Works fine.

[Avon]

One more thing i forgot to mention...

You probably dont have serivice at your modem period..
What I do when this happens is, I hide my mac in the closet and set up a PC. And call the repair man. He later fidles with the PC. Installs this, does that figures the problem is on his end and fixes it. Usualy by crimping new ends on the incomeing cable.. Has happend more than one.

Don't let these idots touch your mac. And don't let them see it. They freek out.

I am in Livingston NJ, and I really cant complain that much about the service. It goes down every 3 or 4 months for a day or two and drives me up the wall, but its better than any other ISP I have ever had.. And at 200+ K/sec its a deal for 40 bucks...

[malvarru]

Thank you all for your responses. Such a wealth of information! I will try with the gateway router solution. As you can tell I am very novice in this matters, so here is some novice questions: how do I clone a windows ip address? Once I connect the router, should I let it set automatically? If so, will it still use my computers ip, thus perpetuating the problem?

Thank you for your knowledge and patience.

[Big Mac]

When I was using PacBell DSL (which provided relatively poor service), there was a period of time after Win XP came out that I couldn't achieve a connection. The poor customer service wouldn't give me a technical answer but simply told me that Mac customers were having problems since their upgrade. I now understand that it could be an MAC blocking issue. I've since switched to Adelphia Cable access, and the service has been so much more reliable.

A router is definitely a good investment in any case. I've been very happy with the Asante FriendlyNet. You probably won't want to clone the MAC address, since that will just reproduce the problem if it's MAC based.

[businezguy]

I agree with the idea that you should purchase a router. That will most likely resolve your issue.

I am from New Jersey and very much enjoy Comcast. However, I do use a router so maybe that is why I am not seeing the issue.

[CIA]

Why is this back in the Powermac forum?

[Scotttheking]

Originally posted by CIA:
Why is this back in the Powermac forum?

No clue, but it's on it's way to Networking now.

[ghporter]

Originally posted by Avon:


I don't think thats possible or even legal. If they did all you would have to do is buy an ethernet card. The only way you cant access certain high speed internet connections is with companies that use propritary software for the PC that verify who you are before you sign on. I dont thin there are many ISPs that do this anymore, its bad for business, not everyone owns a PC.

Once again, I have had Comcast for 3.5 years. Works fine.

Avon, it is unfortunately both possible and (depending on the service agreement) legal. Most cable modems can be instructed to authenticate certain network card MAC addresses, and the more recent ones can be given more specific instructions, such as "allow all but those starting with..." This allows selectively disabling AirPort systems, because the MAC of AirPort Base Stations begins somewhat differently from Apple NICs.

As for "Comcast" being the culprit, it's more a question of "Comcast in City X," than "Comcast" overall. Some franchises do this sort of MAC filtering while others don't. I'm glad you aren't having problems with your service, but a lot of people do-Rogers customers, for example.

I see this issue as a great reason for Apple to upgrade AirPort firmware to allow the user to clone his/her NIC's address. That function sort of makes the cable provider's stupidity moot.

[malvarru]

Thank you all! I purchased a gateway router, and as soon as I installed it, the computer started gretting a valid ip address and I was online again. These forums are certainly an incredible source of info. I regret not knowing about them before I spent $200 in a 'so-called' mac specialist that fixed nothing. I also don't know why, if this is such a common problem, the technicians from customer support at comcast haven't found, or are not suggesting, such a simple solution yet...

[ghporter]

Congratulations on being back in the fast lane! The only advice I can give you now is to go through the user's manual for your router and enable every security feature you can. CHANGE YOUR ADMIN PASSWORD FIRST! (Sorry, was that too loud?) Block WAN requests (or pings, as they're sometimes called), and don't open any ports that don't REALLY need to be open.

A gateway router can be your friend for many reasons, but (once you started getting your IP again) security is one of the best.

Cheers!

[Avon]

Originally posted by GHPorter:
Avon, it is unfortunately both possible and (depending on the service agreement) legal.

Wow. Thanks for the info. Pure criminal if you ask me. I guess it is really advisable to purchase a router that can change their MAC adress eh?

Criminal! That pisses me off.

[Avon]

Originally posted by malvarru:
if this is such a common problem, the technicians from customer support at comcast haven't found, or are not suggesting, such a simple solution yet...

When i first got my modem, they where really pressuring me to buy two cable modems to connect two computers.

CRIMINALS.