Help me to secure my local Imac network.
November 21, 2011 9:32 AM   Subscribe

I can't seem to password protect my local network for my Imac & Mac laptops. Help me, please.

I have set up a network on my Imac10 using Airport. When I try to enable a password, neither my iBook G4 laptop or my PowerBook G4 laptop is allowed access - I keep getting an "Invalid Password" message, despite the fact that it is not an invalid password I'm entering (I have checked & re-checked many times).

When I disable the password, both laptops have no problem joining the network.

I have erased the login key on the keychains of both laptops and this hasn't solved the problem either.

I have checked the Apple forums & have not found any solutions yet.

Not having a password is really not an option as there is sensitive data on all computers.

Any help would be very appreciated!
posted by jammy to Computers & Internet (11 answers total)
Response by poster: hal_c_on > do you mean the settings in Airport under System Preferences? i did try that already (& should have said so above)... how/where to change the channel?

odinsdream > i am using the iMac as the base station. it is connected to the web via ethernet/cable modem. and thanks for the extra security advice. both laptops have strong passwords. i mainly want the laptops to be able to surf the web using the same connection. i'll only be file sharing on an infrequent basis.
posted by jammy at 9:53 AM on November 21, 2011

G4's don't do WPA encryption very well, so you may be stuck using WEP. Just to check, start with a 40-bit key and a 5 character password. If that works, you can try to move up from there. If that doesn't work, it's probably best to just buy a cheap wireless access point.
posted by advicepig at 9:59 AM on November 21, 2011

Response by poster: advicepig > i did try using a WEP 40-bit key & 5character password - no luck.

given that my iMac is already serving as a wireless access point, how will buying another one help? are there particular brands you could recommend? i've already invested a good deal of $$ here & would prefer to fix this (i.e. get these computers to work as they should) instead of buying more stuff, if possible.
posted by jammy at 10:08 AM on November 21, 2011

odinsdream is mostly correct, WEP will not protect your network against anyone with a small amount of technical savvy. However, if you want to continue troubleshooting:

The next step if reconfiguring all computers involved is to reset your network settings. If you are on versions older than 10.4 the steps may be slightly different, but otherwise do the following

navigate to /Library/Preferences/SystemConfiguration

delete or otherwise remove the files '', 'NetworkInterfaces.plist' and 'preferences.plist'. You may be asked to confirm your administrator password to do this.


This will completely reset your network settings to their out-of-the-box defaults. Then proceed to configure the network from scratch.
posted by fearnothing at 10:26 AM on November 21, 2011

Apple did a Windows/Office XP thing with the wireless names. The WiFi device is an Airport. The wireless card in the machine is an AirPort card. This gets confusing so I am going to ask to make sure: If I understand you here, you are using the network sharing on one computer to share access with the others, correct? Or when you say Airport, do you mean the actual, single-purpose WiFi device rather than the card in your iMac - that is, your iMac is connected to the network directly and there is an external AirPort device also connected that is sharing the network?

If it's the built-in card plus internet sharing, everything should work if all the devices are of similar vintage and OS, but who knows. If it's the external device, run the AirPort Setup Assistant in the Utilities folder to connect and change settings.

If you are having trouble with the built-in card it really, really is easier and more future-proof to use an external router to do the work for you. It needn't be expensive. You can probably pick up a reliable A/B/G router dirt cheap if you don't want to buy anything draft N. My home wireless setup cost me a total of $2 using salvaged and yard sale parts (two old WRT54G routers, one 4 port and one 8-port hub - I spent way, way more on cables and network jacks than I did on hardware). This connects an iBook, a G4 Mini, and a pair of newer Intel MacBooks.

Be aware that sometimes - SOMETIMES but not always - on older Macs when connecting to the network you may need to preface your password with a dollar sign for it to work properly. Give it a shot. Can't hurt. And with some hardware, you can't enter the "simple" password, you need to enter the longer hex coded one. Even if that is a pain in the butt to do.
posted by caution live frogs at 10:34 AM on November 21, 2011

how will buying another one help

It will replace this bit of Mac OS X infrastructure, which is apparently causing you frustration, with a dedicated appliance that, in all likelihood, will Just Work.

It will allow you to connect to the internet on your laptops without leaving your iMac on all the time.

I added one of these to my parents' network [supports their iPad and family phones/laptops/etc.]. $15 and ten minutes to set it up and I never have to think about it again.
posted by chazlarson at 11:07 AM on November 21, 2011

"A new piece of equipment won't make older laptops be able to use WPA, since that's a function of the specific laptop model and the wireless chip"

Sorta - but afaik, all the G4 models came with airport extreme cards which can handle WPA from OS X 10.3.6 or therebouts.

I'll not comment on Apple's intelligence in naming both their routers and wireless cards "Airport" and "Airport Extreme"…

The iMac10 (I presume you mean a 2009 or later model?) should be able to act as a WPA access point - although I have a vague memory that the AEx cards used in G4 models can't do WPA when running as an access point, only when used as clients.

But the G4 iBook / PowerBook? AFAIK, they can only do WPA-PSK + TKIP encryption. Which means you'll have to set the iMac up to provide that - not WPA2, and not AES.
posted by Pinback at 12:23 PM on November 21, 2011

Response by poster: To clarify: my iMac is connected directly to a cable modem & i'm trying to use the built-in card for internet sharing.

WPA isn't even an option in System Preferences>Sharing. It only offers 40-bit & 128-bit WEP encryption... which apparently is useless (why then is Apple offering it at all?).

But the G4 iBook / PowerBook? AFAIK, they can only do WPA-PSK + TKIP encryption. Which means you'll have to set the iMac up to provide that - not WPA2, and not AES.

How do i do this?

And how do I check the laptops to see what they support?

(Thank you all for your answers)
posted by jammy at 5:40 AM on November 22, 2011

Huh! It turns out my "vague memory that the AEx cards used in G4 models can't do WPA when running as an access point" is actually "No Macs support anything higher than WEP when internet sharing over wireless". Go figure…

Which means your best bet is to buy a separate wireless router as advicepig etc. have suggested. Personally, I'd recommend the Airport Express or Airport Extreme - the Express if your cable modem has more than 1 ethernet port, the Extreme if it doesn't (because, amongst other things, it has a built-in ethernet switch). But pretty much any cheap wireless router will do.

"given that my iMac is already serving as a wireless access point, how will buying another one help?"

Because Internet Connection Sharing, be it on Windows or OS X, is really just a short-term ad-hoc solution. Your basic requirement is to convert an ethernet connection from your modem to an ethernet connection for your desktop and wireless connections to your laptops etc. That's exactly what a wireless router is designed to do; it's the right tool for the job…
posted by Pinback at 2:59 AM on November 23, 2011

Response by poster: ok, thanks for all the answers, metafiltarians. i appreciate it.

i will stop shaking my computer & yelling "why won't you work like you're supposed to!" and look into getting a wireless router.
posted by jammy at 5:46 AM on November 24, 2011

Response by poster: actually, i'll throw out one more question if anyone's still listening: should i be worried in the first place that anyone would try to tap into my local network in the first place? i live in a small college town in a tiny apartment complex. there's a dozen or so uniquely named networks in the immediate vicinity.

and maybe i should just encrypt whatever info is sensitive (using GPG, e.g.) & leave it at that?
posted by jammy at 5:57 AM on November 24, 2011

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