turning on my macbook airport breaks internet connection for the entire network

last year i never had a problem connecting my macbook pro to my house's wireless internet. now, the internet will be working fine for all other pcs on the network, but the moment i turn on my mac, no one (including myself) can use the internet. i have to turn the airport off and even go as far as shutting the computer down so everyone else can use the internet. i have bittorrent apps on the computer, but they aren't on or running...what is going on? now my entire family hates all macs because they think they mess everything up.

Do you have your Mac set for DHCP or a manual IP address?

Macs do not take over networks like that unless they are set up incorrectly as would a Windows machine set the same way.

dhcp. is that the correct one?

Are you checking that under Network, Airport? If it's set to DHCP it should not be interfering with their network.

Ignore my IP address as it's a special set up here to keep neighbors out.

yes, its that exactly. still having problems.

When you connect to their network, what IP address shows up on your Mac? What Mac is this and what version of OSX? Also what router do they own?

IP address is: 192.168.1.105
router 192.168.1.1 subnet mask 255.255.255.0
my comp is a:
Macbook Pro (2008), OSX 10.5.6

our router is:
linksys wireless-g 2.4 gHz broadband router

That really makes no sense at all. Everything looks right. I use all Linksys here (WRT54GL) and have 20 systems (Macs and Windows) all getting IP's from the Linksys and never an issue unless I manually configure a system to use an IP that is already in use.

Have you tried power cycling the Linksys router? Also what encryption is the router using for WiFi? WEP? WPA?

Ok tell me if this makes any sense. My mac was plugged into a power adapter this morning, and the internet worked perfectly. i then unplugged my computer (which was fully charged) and the moment I did, the internet cut out again. i had to restart my router and plug my comp back in to get it working normally. yesterday, when my mac was causing all those problems, it was also not plugged in. what's going on?!

thesoorae,

You arent crazy! The same exact thing was happening to me. Every time I tried to connect to my wireless network using my Macbook Pro (OSX 10.6), it would destroy my home network... other machines on my networ could no longer resolve hosts. Turning my airport off would make the problem resolve itself in just moments, and as soon as I turned it back on all the machines would loose connectivity! This is definitely repeatable.

I signed up here just to post, because I thought *I* was going crazy. I just deleted a bunch of preferences from /Library/Preferences/SystemPreferences, and I'm about to turn on my Airport again to see if it helped. I'll post this first in case I loose connectivity on this machine, and report back.

I have Verizon DSL -- A Westell 6100F modem connected to a NetGear RangeMax router.

Thesoorae,

That seems to have fixed my problem!

I was down for several hours, rebooted a number of times and regardless when I tried to connect my MBP to my wireless network, it would immediately break my network! After rebuilding my preferences, it seems to have fixed the problem.

Try this:

Move the following files out of /Library/Preferences/SystemConfiguration

com.apple.airport.preferences.plist
com.apple.network.identification.plist
NetworkInterfaces.plist

I used terminal to move them to my home directory. You'll need root access, so you'll have to enter your password in finder, or use the 'sudo' command if doing a 'mv' it in terminal.

Then reboot your machine in safe mode (hold down shift while booting) log in, go to System Preferences->Network, then under Network Name, select "Join other network...", enter your network name (and security type / key if required), go ahead and apply that then reboot normally.

This fixed the problem for me, but it really leaves me wondering WHAT IN OSX CAUSES THIS?!? One machine's wireless settings causing the entire network to crap the bed? Its not just a specific router either because you have a LinkSys and I have a NetGear. I still have the plist files that were seemingly causing the issue. Maybe if I get time, I'll drop them back into place and see if it can reproduce the problem.

Then I can bring my MBP over to friends houses and jam their internets just for grins. =)

If anyone has any idea whats going on with this, I'd like to hear it.

thanks

thanks, seems like sort of a complicated procedure...strange that that happens. after the holidays i moved out of the house, and this problem hasn't happened again anywhere else (strange). but if it does, i will try what u suggested. thanks again.