# invalid IP address on my Mac



## bizarrethings (Dec 23, 2007)

*Help!!* I have contacted Comcast for help with this but they are basically useless when it comes to macs. One woman actually asked me to open up my control panel (I am using OSX 10.4 and she new this.) 
Here's the stats: G4 destop, OSX 10.4, motorola modem (no router), set to dhcp, in network configurations I only have built-in ethernet checked and at the top of the list, I have disconnected the modem and rebooted it several times. Also, I don't always get a bad IP address but often enough that I am now affraid to turn off my mac. A bad address starts with 169 and my good addresses start with 71. Is there something else that I need to try? Could it be the modem is going bad?


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## Satcomer (Dec 23, 2007)

Comcrap is famous for being bad toward users. When you change devices connected directly to a cable modem you have to due things in a certain steps.

1) Connect the Mac to the modem with a KNOWN GOOD ethernet cable.
2) Power the Mac down.
3) Power OFF the cable modem and leave it off for 10 minutes (enough time for the Comcast DHCP server to recycle your IP).
4) Power up the Mac and let it boot up.
5) In OS X go to System Preferences->Network and see if the if you get an valid IP.

Remember to verify you have a good Ethernet cable. Good Luck.


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## bizarrethings (Dec 23, 2007)

How do I know if the ethernet cable is faulty or not?
Thanks for you response!


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## Kees Buijs (Dec 24, 2007)

bizarrethings said:


> How do I know if the ethernet cable is faulty or not?
> Thanks for you response!



Use it with someone elses computer / modem / router. 

If you boot directly into a user, you can run into problems too. I now get the user seelction menu (on a single person used mac) to prevent some issues with the network.

You can try after e.g. a few minutes to release / renew your ip lease. This might take some time, but should lead to getting an address. Maybe a other solution is setting the address static (if your ip number is indeed static).


Good luck, Kees


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## Satcomer (Dec 25, 2007)

bizarrethings said:


> How do I know if the ethernet cable is faulty or not?
> Thanks for you response!



It will be quicker to go to your local electronic brick store and buy a CAT 5E or 6 cable to use. Cable testers are not cheap! Also if you have another device test the cable with that (if it is already working on a network good).


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